Complication, in
medicine, is an unfavorable evolution of a
disease, a
health condition or a
therapy. The disease can become worse in its severity or show a higher number of signs,
symptoms or new
pathological changes, become widespread throughout the body or affect other organ systems. A new disease may also appear as a complication to a previous existing disease. A medical treatment, such as
drugs or
surgery may produce
adverse effects and/or produce new health problem(s) by itself. Therefore, a complication may be
iatrogenic, i.e., literally
brought forth by the physician.