Chronic constipation is one of the most frequent non-motor symptoms in Parkinson's disease (PD), and impairs patients’ quality of life.

The aim of this pilot study was to assess the efficacy and the tolerability of STW5, a phytotherapeutic agent composed of nine plant extracts, for the treatment of constipation in patients with PD.

We carried out an open monocentric study of STW5 in the treatment of constipation in parkinsonian patients. Forty-four PD patients with a mean age of 66.4±7.3 years (range, 35-78), a mean disease duration of 12.6±5.4 years (range, 3–27) and with constipation defined by Rome III criteria for functional constipation were included. Following a two-week laxative-free baseline period, all the patients were treated with 20 drops STW5 t.i.d for 28 days, after a seven-day titration period. Treatment efficacy was defined as marked improvement of stool frequency with an increase of three exonerations during the last week of treatment when compared to the week before the initiation of treatment. Responder rate for stool frequency was estimated at 29/45 patients.

An increase of stool frequency≥three eliminations/week was observed in only four out of 44 patients (9.0%) at the end of the study. The only significant difference observed before and after treatment was a decrease in stool consistency (P=0.0272).

Our results suggest that STW5 has a safety profile but is not effective as a phytotherapeutic agent in constipation related to Parkinson's disease.