OBJECTIVETo determine the therapeutic efficacy and elucidate the probable pharmacological mechanism of Zhizhuwan (ZZ), a known formula for GI/Dysmotility and constipation in Traditional Chinese medicine, in managing constipating diabetes mellitus (DM).

METHODSubjects, composed of both males and females, ranged from 55 to 76 years of age, and had constipating DM. Subjects with severe colon, rectum, heart, renal, or hepatic disease, obesity and those on medications known to alter gastrointestinal motility were excluded. 28 healthy subjects were also recruited. The study group (n = 28) received 90 g per day of ZZ and the control group (n = 28) received 30 mg per day of cisapride for a 1 month period. Conservative therapy was similar in both groups and administered by a person blinded to randomization code. Patients were assessed pre-treatment and post-treatment by a blinded interviewer. A constipation visual analogue scale (CVAS) was constructed to evaluate the patients' constipation status. To analyze neuropeptides motilin (MTL), vasoactive intestinal polypeptide (VIP), substance P (SP) levels in plasma, a radioimmunoassay technique was adopted. Data were analyzed for treatment effects using the "t" test.

RESULTBase line characteristics were similar in both treatment groups. There were significant effects on symptom relief, increases in serum SP level, and decreases in VIP level in both groups (P < 0.05). ZZ was significantly more effective than cisapride in ameliorating patients' subjective symptoms of defecating and stool frequency, and increasing serum SP level (P < 0.05).

CONCLUSIONZZ is beneficial in constipating DM via increasing SP levels and decreasing VIP levels of serum.