α-Lipoic acid, or thioctic acid, (ALA) is the most applicable pharmacological drug for treatment of diabetic polyneuropathy. The article explores the results of experimental studies on the α-lipoic acid effect on mechanisms of peripheral nerves affection in hyperglycemia as well as the data of numerous randomized controlled trials and meta-analyses on studying ALA efficacy in symptomatic diabetic polyneuropathy. It has been shown that amelioration of patients with diabetic polyneuropathy is observed both for ALA infusions and tableted form of the drug. The authors conclude that α-lipoic acid is a drug for treatment of pathogenetic development mechanisms of diabetic polyneuropathy with the best proven efficacy.