In Parkinson's disease-affected patients suffering from constipation, multi-strain probiotics can enhance stool consistency and frequency along with a sense of complete bowel evacuation. However, it does not have a profound effect on motor functions.

A triple-blind, randomized controlled trial was conducted to assess the impact of multi-strain probiotics on motor function and constipation among individuals with Parkinson's disease (PD).

Twenty-seven individuals with PD who met the ROME IV criteria for functional constipation were enrolled in the study. The major endpoint, estimated both pre- and post-intervention in both the probiotic and placebo groups, focused on defecation frequency.

Additionally, the motor function measured using the Unified Parkinson’s Disease Rating Scale (UPDRS) laxative usage, consistency according to the Bristol Stool Scale, and the perception of complete evacuation were the secondary endpoints ascertained. The study had a duration of eight weeks, during which both groups received education on lifestyle modifications.

Out of the 30 subjects initially included, with 15 in each group, there were 13 women and 17 men. However, three patients ceased their involvement in the study. An analysis conducted between the two groups revealed a noteworthy increase in bowel movement frequency, with the probiotic group experiencing an elevation to 4 [3 - 5] compared to the placebo group's rise to 2 [2 - 3].

Stool consistency also exhibited improvement in the probiotic group. No discernable differences were noted in the remaining measured outcomes. Upon within-group analysis, it was observed that both the placebo and probiotic groups demonstrated improved stool consistency, but improvements in stool frequency and the sense of complete evacuation enhanced substantially only in the probiotic group.

Probiotics may be beneficial for alleviating gastrointestinal symptoms in PD patients but do not appear to impact motor symptoms within an 8-week timeframe. Additional investigations with longer-term follow-up are recommended to explore the potential long-term effects.