The use of acetyl L-carnitine, or of one of its pharmaceutically acceptable salts, is described for the preparation of a medicament useful for the prevention of painful peripheral neuropathy in patients suffering from type 2 diabetes, in which said symptoms are selected from the group consisting of pain, paraesthesia and hyperaesthesia, in which the acetyl L-carnitine is administered orally at a dose of at least 3 grams/day.