A Chinese herbal formula had been found to be effective for functional constipation by a study carried out in Hong Kong. The formula Ma Zi Ren Wan (MZRW – composed of Huo Ma Ren [Fructus Cannabis], Da Huang [Radix et Rhizoma Rhei], Bai Shao [Radix Paeoniae Alba], Xing Ren [Semen Armeniacae Amarum], Zhi Shi [Fructus Aurantii Immaturus] and Hou Pu [Cortex Magnoliae Officinalis]) was first mentioned as a treatment for constipation in the Shang Han Lun (Discussion of Cold-induced Disorders). As part of a prospective, randomised controlled clinical trial, 120 subjects with functional constipation were randomised into two groups. One group received MZRW, while the other received a placebo over an 18-week period (two weeks of run-in, followed by eight weeks of treatment, and eight weeks of follow-up). The MZRW group was found to be superior to the placebo group in terms of increased complete spontaneous bowel movements (CSBM), as well as reduction in severity of constipation, straining at evacuation and use of rescue medication. Significant benefits for the MZRW group versus placebo in terms of response rates (participants with a mean increase of CSBM ?1/week) were noted during the treatment phase (43.3 percent versus 8.3 percent) and these benefits were sustained during3 the follow-up period (30.0 percent versus 15.0 percent). Adverse effects affecting the lower gastrointestinal tract (abdominal pain/cramping, bloating, diarrhoea, and passing gas) were more common in the MZRW than placebo group (13.3 percent versus 3.3 percent). The authors note that these side effects are common with laxatives and suggest that they may be related to chrysophanol, an active component of Da Huang.
Chinese herbal medicine for functional constipation: a randomised controlled trial.
Hong Kong Med J. 2013 Dec;19 Suppl 9:44-6.