The short answer: It takes most people 2 to 3 weeks to feel significant benefits when they start taking probiotics. That's because probiotics need time to accomplish their three key goals: increase your good bacteria count, decrease your bad bacteria count, and reduce inflammation.

Some people take a daily probiotic supplement to maintain their general wellness. You might want to do this if you're prone to gut health issues and you notice it helps. A healthy gut microbiome can boost your overall immunity, reduce inflammation and help keep your bowels regular.

People with very weak immune systems, such as those undergoing chemotherapy, should not take probiotics due to risk of infection.

Prebiotics are shown to improve stool frequency and consistency, and when combined with probiotics may provide even more benefits for constipation.