When their numbers increase beyond the normal amount, probably due to trauma or lack of hygiene, it generally leads to a pathogenic event. Streptococcus and Staphylococcus are two examples of such bacteria. Streptococcal bacteria are known to cause several diseases such as streptococcal pharyngitis, meningitis, bacterial pneumonia, endocarditis, pink eye and even necrotizing fasciitis, known as flesh-eating bacteria, in which rare but cause necrosis of the superficial layers of tissues and fascia. Staphylococcus can cause many diseases, most commonly food poisoning and is also known to cause sialadenitis, an inflammation of a salivary gland. Although most of these diseases begin as relatively minor problems, they can worsen if left untreated to cause a systemic inflammatory response in which shock, severe vasodilation, and even death can occur. Microorganisms of the gastrointestinal tract, which are predominantly anaerobic, can cause intestinal abscesses and peritonitis despite playing a significant role in the conversion of bile acids and the production of vitamin K and ammonia in the large intestine. In the vagina, transient organisms can often cause vaginitis. A common culprit is the candida fungus. There are many species of candida and they are among the causes of the most common fungal infections. Candida albicans is one of the most