3 patients developed transient cholestatic jaundice after administration of prajmalium bitartrate, a class I antiarrhythmic drug. The leukocyte inhibition tests showed 4%, 12% and 15% inhibition, respectively, while eosinophilia was seen in all 3, supporting the assumption that the transient hepatic damage was due to drug exposure. Discontinuing the drug resulted in improvement in the clinical and biochemical findings.