Chinese Herbal Retention Enema for the Treatment of Ulcerative Colitis

This article demonstrates a Chinese herbal retention enema method for treating ulcerative colitis, which can effectively improve patients' clinical symptoms and quality of life.

Ulcerative colitis (UC) is a globally prevalent and refractory disease that imposes a substantial socioeconomic burden, with no universally effective treatment currently available. Traditional Chinese medicine (TCM) demonstrated promising therapeutic potential in UC management, particularly through the application of Chinese herbal retention enema, which is gaining increasing international recognition. This method involves the rectal administration of an herbal decoction, which is retained for a designated period to ensure optimal contact with and absorption by the colonic mucosa. Compared to oral administration, this method offers distinct pharmacological advantages by bypassing hepatic first-pass metabolism, enhancing therapeutic effects, and minimizing systemic side effects. This study presents a comprehensive protocol for Chinese herbal retention enema in UC treatment, including patient assessment, material preparation, position selection, enema administration, postoperative care, and emergency management. A clinical trial was conducted with 22 UC patients divided into control and enema groups. Therapeutic outcomes were evaluated using individual symptom scores and the Inflammatory Bowel Disease Questionnaire (IBD-Q). The results indicated that Chinese herbal retention enema had a more significant advantage in improving clinical symptoms (mucopurulent bloody stools and abdominal pain) and quality of life (intestinal symptoms, systemic symptoms, and social functioning) compared to the control group (p < 0.05). These findings suggest that Chinese herbal retention enema represents an effective, well-tolerated, and patient-adaptable therapeutic approach, offering a promising complementary treatment option for UC management.

Ulcerative colitis (UC) is a chronic, nonspecific inflammatory bowel disease primarily affecting the colon and rectum, characterized by persistent or recurrent diarrhea, mucopurulent bloody stools, abdominal pain, tenesmus, and varying degrees of extraintestinal symptoms¹. As a growing global health concern, UC exhibits a steadily increasing annual incidence, afflicting approximately 5 million patients worldwide in 2023, thereby imposing substantial burdens on healthcare systems and societies^2,3. Despite advances in pharmacological interventions, current therapeutic strategies remain nonspecific and suboptimal. Mainstay treatments, including 5-aminosalicylic acid derivatives, glucocorticoids, immunomodulators, and biologics, are frequently associated with severe adverse effects. For example, mesalazine often causes pancreatitis, cardiotoxicity, and hepatotoxicity⁴, while corticosteroids commonly lead to weight gain, osteoporosis, and gastrointestinal bleeding⁵. Moreover, these medications tend to induce drug resistance and demonstrate limited efficacy in preventing disease recurrence⁶. Moreover, the high cost of some drugs places considerable economic strain on patients' families⁷. Thus, there is an urgent need to develop safer and more cost-effective therapeutic alternatives.

Traditional Chinese Medicine (TCM) possesses a unique theoretical system, with medicinal substances primarily derived from natural sources such as plants, animals, and minerals, offering potential multi-target therapeutic effects, relatively favorable safety profiles, and economic accessibility⁸. With a documented history spanning thousands of years in the management of UC, TCM has garnered increasing validation for its ability to alleviate symptoms, reduce recurrence, and minimize adverse reactions^9,10,11. Given the specific anatomical location of UC, local administration through the colorectal route is often more beneficial than oral administration^12,13. Historical records indicate that as early as 200 AD, Chinese herbal retention enemas were employed in clinical practice¹⁴. This method involves the rectal administration of herbal decoction, which is retained for a designated period to ensure optimal contact with and absorption by the colonic mucosa¹⁵. In recent years, the Chinese herbal retention enema technique has gained international recognition and has been applied to various conditions, including acute pancreatitis¹⁶, chronic kidney disease¹⁷, and gynecological disorders¹⁸. Its application is particularly notable in colonic diseases^19,20. Compared with oral drug administration, Chinese herbal retention enema delivers active compounds directly to the site of pathology, bypassing first-pass hepatic metabolism and minimizing degradation by digestive enzymes. This enhances the bioavailability of active components while reducing gastrointestinal irritation and systemic toxicity²¹. Notably, the rich vascularization and thin-walled venous structure of the rectal mucosa facilitate rapid drug absorption, promoting the resolution of inflammation and the repair of tight junctions within the intestinal mucosa, thereby improving overall mucosal integrity²². Although Western medicine has also adopted local administration methods, such as rectal delivery of 5-aminosalicylic acid and corticosteroids, to minimize systemic side effects, comparative evidence indicates that Chinese herbal retention enemas demonstrate superior therapeutic efficacy alongside a more favorable safety profile²¹.

Despite these advantages, the clinical application of Chinese herbal retention enemas remains limited due to the absence of standardized protocols and insufficient familiarity among healthcare professionals. Therefore, this paper systematically presents a standardized protocol for administering Chinese herbal retention enemas in the treatment of UC. The overall aim is to provide a detailed description of the procedure, including key steps and precautions, to ensure its clinical feasibility, reproducibility, and broad applicability in clinical practice.

The protocol has been approved by the Ethics Committee of the Hospital of Chengdu University of Traditional Chinese Medicine (Ethics No.: 2024KL-182-01). The operational procedures comply with the clinical guidelines of the Hospital of Chengdu University of Traditional Chinese Medicine. Informed consent was obtained from all patients for participation in the study.

1. Patient assessment

1. Confirm that the diagnosis meets the criteria for UC²³. Verify the patient is willing to accept Chinese herbal retention enema treatment and has signed an informed consent form.
2. Exclude patients with serious complications, such as lower gastrointestinal bleeding, obstruction, perforation, severe heart failure, liver or kidney dysfunction, hematological disorders, malignant tumors, mental disorders, or a history of allergy to Chinese herbs. Also, exclude patients with perianal skin lesions, severe hemorrhoids, or those who have undergone anal, rectal, or colonic surgery within the past 3 months. Exclude pregnant or lactating females.

2. Patient preparation

1. Instruct the patient to empty their bowels and bladder 30 min before the enema procedure. Explain the procedure steps, safety precautions, and therapeutic benefits in detail to alleviate anxiety and ensure patient cooperation.
2. Perform a routine cleansing enema prior to the herbal retention enema if fecal residue is present. Prepare a warm saline solution (approximately 500-1000 mL) at body temperature (37 °C-40 °C). Close the enema bag tube clamp to prevent leakage and fill the enema bag with warm saline.
3. Position the patient in left lateral decubitus with knees flexed. Loosen the clothing and pull the pants down to mid-thigh, fully exposing the anal area. Lubricate the rectal tube with paraffin oil and gently insert it into the anus to a depth of 7-10 cm, guided by the graduated centimeter markings on the proximal segment of the tube.
4. Hang the enema bag on the infusion stand, ensuring that the liquid level is approximately 40 cm above the anus. Open the clamp of the rectal tube and allow the warm saline solution to flow slowly into the rectum. Once the infusion is complete, close the clamp, carefully remove the rectal tube, and clean the anus with wet tissue. Instruct the patient to lie flat and retain the saline for 5-10 minutes to facilitate adequate bowel distension and cleansing.
5. After the retention period, provide the patient with a bedpan to evacuate the saline and fecal. Assess the clarity of the expelled solution to determine whether further enemas are required. Repeat the enema procedure 2-3 times, if necessary, until the discharged saline is clear and free of fecal residue. If the patient develops pallor, cold sweat, severe abdominal pain, or panic, stop immediately and notify the physician.

3. Material preparation

1. Preparation of herbal decoction
   1. Weigh the following herbs (Figure 1): Sanguisorba officinalis L. (Sanguisorbae radix) 20 g, Sophora japonica L. (Sophorae flos) 10 g, Portulaca oleracea L. (Portulacae herba) 10 g, Baphicacanthus cusia (Nees) Bremek. (Indigo naturalis) 30 g, Paeonia lactiflora Pall. (Radix paeoniae rubra) 10 g.
   2. Place the herbs in a clay pot. Add enough cold water to submerge up to 2-3 cm. Soak the herbs for 30 min.
   3. Bring the water to a boil, then simmer for 30 min. Filter through two layers of medical gauze and retain the decoction.
   4. Add cold water again to submerge the herbs by 2-3 cm. Bring it to a boil once more and simmer for another 30 min. Filter through two layers of medical gauze and retain the decoction.
   5. Combine the two decoctions and allow it to cool to a suitable temperature (approximately 39 °C-41 °C) for use.
2. Preparation of other materials
   1. Prepare an asepsis enemator for a single-use kit (including a single-use sterile enema device, disposable gloves, a disposable treatment tray, a medical treatment towel, and paraffin oil), a water thermometer, gauze, a cushion, a bedpan, and a privacy screen (Figure 2 and Table of Materials).

4. Treatment procedure

1. Administer conventional treatment to the control group: prescribe oral mesalazine enteric-coated tablets (4 g/day), combined with a personalized herbal decoction. Provide the enema group with additional daily Chinese herbal retention enemas.
2. Confirm the patient's information (name, age, hospitalization number). Ensure the patient has emptied their bladder and bowel. Confirm that the patient has signed the informed consent form. Re-evaluate the patient's condition and assess the patient for any discomfort or adverse symptoms that may contraindicate the procedure. Check the expiration dates and integrity of all equipment.
3. Close the doors and windows and adjust the room temperature to a comfortable level (approximately 22 °C-28 °C). Use a privacy screen to protect the patient's privacy.
4. Wash hands, don gloves and a mask. Inspect the perianal area for lesions or contraindications.
   1. Assess the skin condition: Inspect for redness, swelling, irritation, warmth, tenderness, or discharge.
   2. Examine for hemorrhoids: Palpate and visually inspect swelling, prolapse, or bleeding.
   3. Check for fissures or ulcers: Inspect for cracks, tears, or open sores around the anus.
   4. Examine for abscesses or infections: Palpate for lumps, swelling, redness, pus, or fluctuance.
   5. Ensure perianal hygiene: Clean the area thoroughly to remove fecal residue or debris.
   6. Identify contraindications: Report any concerning findings (e.g., recent surgery or infections) to the physician immediately.
5. Position the patient in left lateral decubitus with knees flexed. Loosen the clothing and pull the pants down to mid-thigh, fully exposing the anal area. Place a medical drape under the buttocks and elevate the hips by 10 cm using a cushion (see Figure 3).
   1. Adjust the patient's position based on the lesion location: for rectal and sigmoid colon lesions, use the left lateral position; for ileocecal lesions, use the right lateral position.
6. Measure the herbal decoction temperature (39 °C-41 °C) using a water thermometer. Close the enema bag tube clamp to prevent leakage. Fill the disposable enema bag with ≤ 200 mL of the decoction and hang it, ensuring the liquid level is no more than 30 cm from the anus.
7. Lubricate the rectal tube tip with paraffin oil. Instruct the patient to perform deep oral breathing. Gently insert the tube 15-25 cm into the rectum.
   1. Adjust the insertion depth based on the lesion location: for lesions in the rectum and sigmoid colon, insert the tube 15 to 20 cm; for lesions in the sigmoid or descending colon, insert 18 to 25 cm.
8. Open the enema bag tube clamp and slowly drip the herbal decoction, adjusting the infusion rate based on the patient's condition and tolerance. Maintain a total infusion time of 15-20 min. Continuously observe the patient and inquire about their tolerance. Adjust the infusion rate or discontinue the procedure if discomfort or the urge to defecate arises.
   1. Stop the enema immediately if the patient shows signs of rapid pulse, pale complexion, cold sweats, severe abdominal pain, or palpitations. Notify the physician immediately.
9. Clamp the tube upon completion. Remove the tube slowly while asking the patient to contract anal sphincters. Cleanse the perianal area with gauze.
10. Instruct the patient to remain in the supine position with hips elevated for 60 min. Provide a bedpan for controlled evacuation after the retention period.
    1. For patients with poor retention (< 30 min), add 2-3 mL of 1% lidocaine to the herbal decoction after physician approval.
11. Dispose of biohazardous waste in designated containers. Disinfect reusable equipment according to the Technical Specification for Disinfection in Healthcare Facilities²⁴. Document the procedure details and the patient's response.

5. Postoperative care

1. Open the windows to ensure proper ventilation. Replace the bed linens with clean sheets.
2. Check for signs of abdominal distension, diarrhea, constipation, or other symptoms. Instruct the patient to avoid straining during bowel movements. Guide the patient to monitor and record daily stool characteristics, including frequency, color, odor, and consistency. Collect stool samples for further examination if abnormalities are observed.
3. Advise the patient to rest and follow a light, easily digestible diet. Prohibit the consumption of hard, cold, raw, high-fiber, spicy, fried foods, and dairy products.
4. Monitor the patient's vital signs (temperature, blood pressure, pulse, heart rate, and respiration rate) at 15 min intervals for the first hour after the procedure. Thereafter, assess the vital signs hourly for the next 4 h. Document any changes in symptoms promptly.

6. Drug efficacy evaluation

1. Primary efficacy indicators
   1. Assess UC symptoms using the individual symptom scores recommended by the Experts' consensus on traditional Chinese medicine diagnosis and treatment of ulcerative colitis (2023)²⁵ Score the following symptoms:
      Diarrhea: 0 (none), 3 (<4 times/day), 6 (4-6 times/day), 9 (>6 times/day)
      Mucopurulent Bloody Stools: 0 (none), 3 (small amounts of pus/blood), 6 (predominant pus/blood), 9 (entire stool composed of pus/fresh blood)
      Abdominal Pain: 0 (none), 3 (mild/intermittent), 6 (moderate/recurrent), 9 (severe/cramping)
      ​Tenesmus: 0 (absent), 1 (present)
   2. Perform a baseline assessment upon admission. Administer the Chinese herbal retention enema daily for 14 consecutive days. Conduct the final efficacy evaluation 24 hours after the last enema. Compare post-treatment scores with baseline scores.
2. Secondary efficacy indicators
   1. Assess quality of life using the Inflammatory Bowel Disease Questionnaire (IBD-Q)²⁶. Evaluate the patient's social function, emotional status, systemic symptoms, and bowel-related symptoms. Higher scores indicate improved quality of life.
   2. Perform a baseline assessment upon admission and a follow-up evaluation 14 days after treatment completion.

This study included 22 UC patients from the Department of Gastroenterology at the Hospital of Chengdu University of Traditional Chinese Medicine. The control group received conventional treatment (oral mesalazine enteric-coated tablets combined with a personalized herbal decoction), while the enema group received additional daily Chinese herbal retention enemas.

The outcome measures of this study were the individual symptom scores and the IBD-Q scores. The individual symptom scores are shown in Table 1. At baseline, no significant differences were observed between the two groups (p > 0.05). After treatment, the control group showed significant improvement in scores for diarrhea, mucopurulent bloody stools, and abdominal pain (p < 0.05) but no significant difference in tenesmus (p = 0.211). The enema group showed significant improvement in all symptom scores, including diarrhea, mucopurulent bloody stools, abdominal pain, and tenesmus (p < 0.05). Compared with the control group after treatment, the enema group had significantly better outcomes for mucopurulent bloody stools and abdominal pain (p < 0.05), while no significant differences were found for diarrhea (p = 0.056) or tenesmus (p = 0.300).

The IBD-Q scores are shown in Table 2. At baseline, no significant differences were observed between the two groups (p > 0.05). After treatment, the control group showed significant improvements in bowel symptoms, systemic symptoms, emotional function, and total score (p < 0.05) but not in social function (p = 0.054). The enema group showed significant improvement in all domains, including bowel symptoms, systemic symptoms, emotional function, social function, and total score (p < 0.05). Compared with the control group after treatment, the enema group had significantly better outcomes for bowel symptoms, systemic symptoms, and social function (p < 0.05), while emotional function (p = 0.828) and total score (p = 0.113) showed no significant differences.

No adverse reactions were observed in either group during the treatment period. This study demonstrates that Chinese herbal retention enemas combined with conventional treatment can significantly improve individual symptoms and quality of life in patients with UC. Compared to conventional treatment, the enema group showed more pronounced advantages in improving clinical symptoms (mucopurulent bloody stools and abdominal pain) and quality of life (bowel symptoms, systemic symptoms, and social function). These results suggest that Chinese herbal retention enemas may serve as a valuable adjunctive therapy for UC. Further research is needed to explore the long-term effects and broader applicability of this treatment approach.

Figure 1: Chinese herbs used for enema. (A) Sanguisorbae radix. (B) Sophorae flos. (C) Portulacae herba. (D) Indigo naturalis (powdered and packed in cloth bags to prevent paste formation during decoction that affects other medicines). (E) Radix paeoniae rubra. Please click here to view a larger version of this figure.

Figure 2: Materials used in the treatment. (A) Prepared Chinese herbal decoction. (B) A sepsis enemator for single-use kit. (C) Paraffin oil. (D) Tissue paper. (E) Medical treatment towel. (F) Disposable treatment tray. (G) Single-use sterile enema device. (H) Disposable gloves. (I) Water thermometer. (J) Gauze. (K) Metal treatment tray. (L) Privacy screen. (M) Bedpan. (N) Cushion. Please click here to view a larger version of this figure.

Figure 3: Illustration of Chinese herbal retention enema procedure. The healthcare provider prepares the Chinese herbal enema decoction, and the patient is positioned in the left lateral position for catheter insertion. Informed consent was obtained from this patient for the photograph. Please click here to view a larger version of this figure.

Table 1: Individual symptom scores before and after treatment in two groups. ^#: Compared with the baseline, p < 0.05. Both intergroup and intragroup comparisons were conducted before and after treatment. If the differences followed a normal distribution, a paired t-test was used; if at least one group did not meet the normality assumption, the non-parametric Wilcoxon signed-rank test was employed. A p < 0.05 was considered to indicate a statistically significant difference. Please click here to download this Table.

Table 2: IBD-Q scores before and after treatment in two groups. ^#: Compared with the baseline, p < 0.05. Both intergroup and intragroup comparisons were conducted before and after treatment. If the differences followed a normal distribution, a paired t-test was used; if at least one group did not meet the normality assumption, the non-parametric Wilcoxon signed-rank test was employed. A p < 0.05 was considered to indicate a statistically significant difference. Please click here to download this Table.

UC is a chronic inflammatory disease primarily affecting the colorectal mucosa. Research has shown that rectal formulations of 5-aminosalicylic acid and corticosteroids can directly target the lesions, effectively reducing systemic reactions and demonstrating higher efficacy and safety compared to oral treatments^12,27. However, these medications are still associated with unavoidable side effects, which has prompted increasing attention to the application of TCM as an alternative or adjunctive therapy.

The herbal retention enema used in this study is based on decades of clinical experience from the Department of Gastroenterology at the Hospital of Chengdu University of Traditional Chinese Medicine. Many UC patients have achieved remission solely through oral and enema administration of herbal medicine, reducing their reliance on 5-aminosalicylic acid and corticosteroids, thereby alleviating their economic burden and stress of life. The enema formulation includes Sanguisorbae radix, Sophorae flos, Portulacae herba, and Indigo naturalis, which are classical TCM remedies for mucopurulent bloody stools. Modern pharmacological studies indicate that the main active ingredients of these herbs possess hemostatic, anti-inflammatory, antibacterial, and immunomodulatory properties^{28,29,30,31,32}. In vivo and in vitro studies have further confirmed their ability to significantly improve UC by inhibiting ferroptosis and oxidative stress, reducing inflammatory responses, and modulating gut microbiota^{33,34,35,36,37,38}. TCM recognizes a complementary relationship between bleeding and blood stasis, with blood stasis being a common pathological factor in UC patients³⁹, which corresponds with modern medical views on microcirculation disturbances in UC⁴⁰. Accordingly, Radix paeoniae rubra is included in the enema formulation to alleviate blood stasis and pain. This herb contains various active components, such as flavonoids, lignans, and tannins, which exhibit anticoagulant, antithrombotic, microcirculation-improving, neuroprotective, and anti-inflammatory activities^41,42. Notably, the herbal components of the enema are not fixed and can be adjusted based on the patient's specific condition to address varying severity and clinical symptoms.

The key steps in this protocol are as follows: The volume of the herbal decoction should not exceed 200 mL, as exceeding this volume may stimulate pressure receptors, triggering a defecation reflex that compromises prolonged retention⁴³. The temperature of the herbal decoction should be maintained between 38 °C and 41 °C to match the physiological rectal temperature (human rectal temperature is 36.8-37.8 °C), thereby minimizing mucosal irritation⁴⁴. The depth of catheter insertion is crucial in Chinese herbal retention enemas. Improper depth can cause patient discomfort and even intestinal injury. If the catheter is inserted too shallowly, the herbal solution may not reach the targeted therapeutic area, reducing efficacy and shortening retention time⁴⁵. Conversely, excessive insertion depth may irritate the intestinal wall, increasing the risk of perforation or other complications. Therefore, correct catheter depth ensures effective drug delivery while minimizing discomfort and potential risks. Additionally, to optimize therapeutic outcomes, patients can be assisted in changing positions to maximize contact between the herbal decoction and the intestinal mucosa, such as left lateral position to prone position to knee-chest position to right lateral position and massage the abdomen appropriately⁴⁶. In the treatment of Chinese herbal retention enemas, it is usually recommended to retain the herbal decoction in the intestine for over 1 h. TCM theory suggests that the therapeutic effects of herbal medicine are closely related to the temporal changes of meridian qi. For UC patients, daily enemas between 5:00 - 7:00 AM or 9:00 - 11:00 PM are more helpful in restoring the physiological function of the large intestine⁴⁷. Therefore, it is advised that patients, if conditions permit, perform the enema every night before bedtime, retain the herbal decoction until morning, and naturally discharge with bowel movements.

While the efficacy of Chinese herbal retention enemas is commendable, potential complications should be considered. For patients who are bedridden or have chronic diarrhea, enemas may increase bowel movement frequency, leading to perianal skin irritation or damage. These patients should gently clean the perianal area with moist wipes, keep it dry, and receive symptomatic treatment if necessary. As an invasive procedure, improper technique or patient anxiety can lead to intestinal damage or perforation. Operators must be familiar with intestinal anatomy, proceed gently, and reassure the patient. If resistance is encountered, adjustments should be made promptly, and repeated insertion attempts should be avoided⁴³.

Several limitations of this method should also be acknowledged. First, as outlined in the contraindications, this method is not suitable for patients with perianal diseases or severe systemic complications. Second, the procedure requires specialized technical skills, which limits the ability of patients to perform it independently at home. Third, as an invasive intervention, it may induce patient discomfort, including abdominal distension, rectal urgency, and transient pain during catheter insertion, which could compromise treatment adherence. Finally, while this method has demonstrated superior efficacy in alleviating intestinal symptoms compared to conventional therapies, its effectiveness in managing extraintestinal manifestations of inflammatory bowel disease, such as arthritis or uveitis, remains inconclusive and requires further investigation⁴⁸.

Despite these limitations, Chinese herbal retention enemas show considerable therapeutic potential. By targeting local action, this method minimizes systemic side effects, making it a valuable adjunct to standard therapies. With further optimization of treatment protocols and broader clinical validation, it could become an indispensable component of inpatient management for UC, particularly for patients with distal colitis who are refractory to or intolerant of conventional treatments.

The authors have nothing to disclose.

This work was supported by the Sichuan Provincial Administration of Traditional Chinese Medicine Scientific and Technological Research Special Project (2024zd004) and the Sichuan Provincial Key Research and Development Project (2024YFFK0171).