What the Evidence Says for Traditional Chinese Medicine Ma Zi Ren Wan for Constipation

September 24, 2021

A common and distressing symptom among patients with a variety of health diagnoses as well as the general population, constipation is characterized by reduced stool frequency, incomplete evacuation, straining, and a sense of anorectal blockage. Nearly 43%–58% of patients with cancer report constipation caused by a variety of factors, including organic, functional, or drug associated. Standard treatment options such as fiber supplements, laxatives, and stool softeners are not entirely effective and can cause adverse effects.

By Jyothirmai Gubili, MS, Eugenie Spiguel, MSN, ANP-BC, and Yen Nien (Jason) Hou, PharmD, Dipl OM, LAc

Traditional Chinese Medicine for Constipation

Ma Zi Ren Wan (MZRW), also known as hemp seed pill, is a traditional Chinese medicine formula consisting of six herbs. Its medicinal history as a treatment for constipation has been documented for several centuries.

After a systematic review, Zhong et al. reported that MZRW was the most commonly used herbal medicine to treat constipation in China. It is also often prescribed for patients with prostate cancer in Taiwan. However, current data of MZRW’s effectiveness are limited to studies conducted in Asian population.  

In a three-armed trial, 291 adult patients with functional constipation were randomized to receive MZRW (7.5 g twice daily), the herbal laxative senna (15 mg daily), or a placebo for eight weeks. The primary outcome was the number of patients with a complete response (increase in > 1 complete spontaneous bowel movement [CBSM] per week compared to the baseline). At the end of treatment period, 68% of those receiving MZRW experienced a complete response, compared to 58% for senna and 33% for placebo. MZRW also significantly increased colonic transit and reduced straining and global constipation symptoms compared to senna and the placebo. And the response persisted at the 16-week follow-up (47.4% for MZRW, 20.6% for senna, and 17.5% for placebo).

Another randomized trial involving 120 adult patients with functional constipation also showed durable improvement in CBSM with MZRW (7.5 g twice daily). At 8 weeks, 43.3% of patients receiving MZRW responded with CSBM compared to 8.3% receiving the placebo; at 16 weeks the rates were 30% and 15%, respectively. In addition, the MZRW group needed less rescue therapy compared to those who took placebo.

Conclusions from a systematic review and meta-analysis (17 trials involving 1,681 patients) further validated that MZRW is safe and effective against functional constipation in Asian populations and that it does not increase adverse events compared to controls. Notably, four of the reviewed studies were conducted in pediatric and adult patients with cancer who had opioid-related and chemotherapy-induced constipation.   

Further research is warranted to determine MZRW’s effectiveness in diverse populations and its potential in mitigating nonfunctional constipation. Studies are also needed to understand MZRW’s mechanisms of action. Preliminary findings suggest that some of its constituent herbs may help reestablish gastrointestinal homeostasis to enhance colonic motility and ease constipation. It may also decrease levels of circulating oleamide, which regulates intestinal motility.

Side effects associated with MZRW include abdominal pain, cramping and bloating, diarrhea, gas, nausea and vomiting, headache, dizziness, difficulty urinating, and worsened rhinitis.

What Oncology Nurses Need to Know

Constipation is a frequent side effect for patients with cancer. Left untreated, it can result in abdominal pain, nausea, vomiting, psychological distress, and more serious complications such as bowel obstruction and perforation. Pharmacologic options may be effective in the short term, but they’re associated with adverse effects such as diarrhea and metabolic disturbances.

MZRW has been shown to be a safe and effective treatment option for functional constipation, and the effects can last even after treatment has ended. Oncology nurses can consider the herbal supplement when discussing constipation management with patients and refer them to licensed traditional Chinese medicine practitioners experienced in working with patients with cancer for proper use.  


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