How long does it take for probiotics to work?

Probiotics, healthy bacteria essential for digestion within the stomach, can assist in decreasing symptoms of diarrhea to around two days, states WebMD. Mayo Clinic suggests different dosing time frames, depending on what ailment is being treated.

Ailments apparently treated by probiotics include vaginal infections, diarrhea, hay fever, high cholesterol and general stomach problems, states Mayo Clinic. Probiotics can be found in yogurt and in a pill form. It should also be noted that no clear evidence has been found that acidophilus, a popular bacterial strain used in probiotics, is effective in reducing signs and symptoms of stomach and intestinal issues.