We performed a case-controlled analysis on the effectiveness of dantrolene and certain dopamine agonists--bromocriptine, amantadine 3,4-dihydroxyphenylalanine, (DOPA)--for the neuroleptic malignant syndrome (NMS). This was based on a review of all known published studies using as controls those cases not treated with these drugs and/or electroconvulsive therapy. In this control group, the NMS-related death rate was 21 percent. Dantrolene alone reduced the death rate to 8.6 percent, bromocriptine alone to 7.8 percent, and amantadine alone to 5.9 percent. We also stratified patients into five levels of severity based on state of consciousness and temperature and showed that the relative reduction in death rate held up at all levels. The dopamine agonists and dantrolene have a therapeutic effect independent of each other.