Throughout the last 20 years, numerous studies have indicated pro-inflammatory activity in patients with an acute schizophrenic episode. In this report, the most relevant findings concerning the cytokine systems in schizophrenia are demonstrated, together with recent studies on gene expression. Findings in humans are supplemented by observations from rodent models of schizophrenia. Furthermore, the current state of both neuroleptic and anti-inflammatory compounds on the immune system is reported, together with clinical data on the effects of anti-inflammatory medications on the course of the acute illness in patients with schizophrenia.