A test to find and characterise the bacteria that cause infections of the lower digestive system is called a stool culture. The test makes a distinction between pathogenic (disease-causing) bacteria and those that are typically prevalent in the digestive tract (normal flora). The test assists in determining whether gastrointestinal symptoms are brought on by pathogenic microorganisms (gastroenteritis). The bacteria in stools are an accurate representation of the microorganisms in the digestive system (gastrointestinal tract). Everybody s gastrointestinal system is home to a group of bacteria and fungus known as normal flora. They are crucial to the process of food digestion and prevent the growth of bacteria that cause illness.