Probiotics are essentially helpful, live organisms, usually bacteria that are used to change or re-establish the intestinal or gut flora and improve our health. These microbes are important because of the roles they play in the human body, where they are believed to be helpful in the prevention and the treatment of various disease as well as allergy treatment and prevention. They are usually administered to our gastrointestinal track through the foods we eat.

Dairy foods like milk and yogurt are usually the most popular foods that probiotics are added to. In addition to their use as additives in foods, probiotics can also be administered in a powdered or capsule form, on their own or as a dietary supplement.

Harmful effects of probiotics can occur where there is cross contamination.