Of a disease or disorder that arises within the body rather than being caused by external factors. (See also exogenous.)
Coming from within the body. Endogenous depression, for instance, occurs as a result of causes inside a person.
From within the body, either a native function or the product of the extended colony...normal flora in the colon are considered endogenous.
adj. 1. arising within or derived from the body. Compare exogenous. 2. formerly (until the 1980s), denoting a type of *depression (also known as melancholia) that was thought to arise totally biologically and therefore without any particular triggers. It stood in contrast to reactive depression, which was supposed to have been primarily triggered by stress or trauma. Today this differentiation is not usually made as the validity of separating these two types of depression could not be proven.
Health Encyclopedia