Probiotics are healthy, live microorganisms that are found mainly in the intestines. They are considered good bacteria that keep digestive problems at bay. You as host nourish these living organisms while they keep the good and bad bacteria in your body well balanced. However, if they are not properly introduced to your system or if you have excessive amount of them, a person may experience mild symptoms abdominal pain, gas, bloating, and stomach upsets. Even if probiotics are good bacteria, people with serious illnesses especially in the pancreas should stay away from it since they can be fatal.