Do probiotics work?

HowStuffWorks notes that probiotics work because they recolonize the stomach with healthy bacteria, which are usually eliminated by antibiotics. Scientists are convinced that probiotics fight toxins and pathogens. Probiotics reduce the risk of diarrhea by 52 percent among patients taking antibiotics.

WebMD points out that probiotics also promote a strong immune system and are effective in treating ulcerative colitis and necrotizing enterocolitis. Mayo Clinic argues that more research on probiotics is needed, but encouraging evidence shows that they reduce severity of flu and colds and treat irritable bowel syndrome. WebMD warns that probiotics can be dangerous for people with serious illnesses or weak immune systems. They are found in supplements and foods, such as yogurt.