Hippophae rhamnoides L. Fruit Extract Relieves Chronic Idiopathic Constipation and Improves Bowel Function: A Monocentric, Randomized, Double-Blind, Placebo-Controlled, Clinical Trial

Background/Objectives: Chronic idiopathic constipation (CIC) is a common gastrointestinal disorder with a global prevalence of about 14%, common in women and elderly population. It often lacks effective treatment. This randomized clinical trial was aimed to evaluate the efficacy and tolerability of Hippophae rhamnoides L. (sea buckthorn) fruit extract in adults with CIC. Methods: A UHPLC-HRMS/MS analysis was performed on the hydroethanolic H. rhamnoides fruit extract to evaluate its composition. Ninety participants were randomly assigned to receive either 500 mg of H. rhamnoides extract or placebo delivered through a capsule daily for 28 days. The primary outcome was the change in weekly spontaneous complete bowel movements (SCBMs), while secondary outcomes included stool consistency (Bristol Stool Form Scale—BSFS), gastrointestinal symptoms, and quality of life (SF-12). Results: Metabolic profile of the extract tentatively identified 75 bioactive compounds, predominantly flavonoids, triterpenoids and phospholipids. H. rhamnoides fruit extract significantly improved SCBM frequency (from 1.5 to 2.6 per week; p < 0.001) and normalized stool consistency (mean BSFS score from 1.4 to 3.5; p < 0.001), compared to no change in the placebo group. Significant reductions in bloating, abdominal pain, and heaviness were observed, while flatulence showed no between-group significant difference. No adverse events or use of rescue treatments were reported. Quality-of-life scores remained largely unchanged, with a non-significant trend towards improved mental health in the treated group. Conclusions: These findings suggest that H. rhamnoides fruit extract is a safe and effective option for managing CIC, offering an alternative to other plant extracts with laxative effects.