Mildronate of 3-(2,2,2-trimethylhydrozinium)propionate, a novel anti-ischemic drug, inhibits the biosynthesis of carnitine from Y-butyrobetaine. Continuous administration of mildronate (200, 400 mg/kg for 10 days orally) to rats exerted a marked antiketogenic action on the animals deprived of food for 48 hours. In the fed rats receiving sodium octanoate a course treatment with mildronate elevated to concentration of ketone bodies in blood serum. Selective regulation of carnitine-independent and carnitine-dependent metabolism appears justified for the treatment of such pathological states as ischemic heart disease, diabetes and obesity.