This article is about the symptom. For the eating disorder, see anorexia nervosa.
Anorexia, or lack of appetite, is a symptom that is common to most illnesses, and is most often the result of infection, the result of the body shutting down the digestive tract to shunt energy to the immune system. If it persists without presenting with a fever, it usually points to a disorder of the digestive tract itself, although it can also be a symptom of certain types of cancers, neurological disorders, or autoimmune conditions.