The causes of schizophrenia are unknown; many etiologies have been implicated but none proven. Renewed interest in immunological etiologies has led investigators to examine the plasma of patients with schizophrenia in which they have found increased levels of some cytokines and antibodies to cytomegalovirus and Toxoplasma gondii. Elevated plasma C-reactive protein is associated with increased risk of later schizophrenia. Prenatal exposure to some infectious agents and increased maternal levels of interleukin-8 during pregnancy are associated with increased risk for schizophrenia. These findings suggest that in a subset of patients, an immunological and, perhaps infectious mechanism, might be involved. This article reviews treatment trials that have an anti-inflammatory or anti-infectious mechanism of action. These include antibiotics, nonsteroidal anti-inflammatory drugs, anti-toxoplasma drugs, monoclonal antibodies, and other drugs effective against inflammatory or infectious diseases. To date, none of these anti-inflammatory compounds have consistently shown efficacy; studies on many promising compounds are ongoing.