Gut bacteria play a role in peristalsis regulation or the control of involuntary constriction and relaxation of intestinal muscles that push stool through the digestive tract. Intestinal bacteria are thought to influence factors that affect gut motility, such as short-chain fatty acids, bile acid metabolism, and enteric nervous system development. Adding a probiotic supplement to your routine may not have immediate effects; however, it may improve and alleviate constipation over time.