Results are reported of a double-blind trial with L-dopa in 39 patients with measles encephalitis. In this treatment series, L-dopa improved the state of awareness and the diffuse disturbances in the EEG. There was a significant difference too, regarding the outcome between patients treated with L-dopa and placebo. The death rate in the L-dopa-treated group was lower and there were fewer mental sequelae. It is suggested, that L-dopa should be used in patients with measles encephalitis.