Carnitine and its use in reducing cardiac toxicity and as a synergist with cytostats

A method of reducing cardiac toxicity in humans which results from the administration to such human of a cytostat selected from the group consisting of Daunomycin, N-acetyl-Daunomycin and Daunomycin oxine, which comprises administering to said human in combination with said cytostat, an amount of .beta.-hydroxy-.gamma.-trimethylaminobutyric acid, a pharmaceutically acceptable salt thereof, an isomer thereof or a pharmaceutically acceptable salt of an isomer thereof sufficient to reduce cardiac toxicity.