Bifidobacterium Animalis for Constipation Relief

Research suggests that certain strains of Bifidobacterium animalis, particularly subsp. lactis, may help relieve constipation by improving intestinal motility, stool hydration, short-chain fatty acid production, and the activity of gut-regulating signaling molecules, based on two supportive animal studies from 2022 and 2025. A third animal study, however, found that among six Bifidobacterium species tested head-to-head, Bifidobacterium animalis was not the standout performer, with Bifidobacterium longum showing stronger effects, which introduces some nuance about whether all Bifidobacterium strains are equally effective. The most rigorous human evidence comes from a 2023 randomized controlled trial that included a probiotic blend alongside fiber interventions, and while results were mixed — active treatments improved stool consistency but not bowel movement frequency compared to placebo — the trial also found that individual differences in participants' baseline gut microbiota may influence who responds to probiotics. Overall, the available evidence is preliminary and largely drawn from animal models and one mixed-result human trial, meaning firm conclusions about the effectiveness of Bifidobacterium animalis for constipation in people cannot yet be drawn.