Abstract: Like the other dithiols, lipoic acid could significantly reduce the toxicity of potassium antimony tartrate. A hypodermic or oral dose of 130 mg/kg of lipoic acid raised the LD₅₀ of potassium antimony tartrate given intraperitoneally in mice from 27±2 to 77±7 and 70±4 mg/kg respectively. By using lipoic acid the subacute lethal effect of potas- sium antimony tartrate was also antagonized. In the acute test, when the dose was calculated on a molecular basis, 2-3 moles of lipoic acid could antagonize the lethal effect of one mole of potassium antimony tar- trate. Within 3 hours after the intraperitoneal injection of LD₅₀ of potassium antimony tar- trate in mice, the administration of lipoic acid could protect all the tested animals from death.