The effects of the cerebral cortex gangliosides have been studied in fifteen patients with peripheral neuropathies through the results of electromyographic examination. The patients were divided into two groups: A - peripheral neuropathy of alcoholic etiology (seven patients); D - peripheral neuropathy of diabetes etiology (eight patients). The medication has been administered 20 mg/day intramuscularly during twenty days. At the end of that period it was verified: 1) a discrete increase of the motor conduction velocity in the patients of the group A; 2) the sensitive conduction velocity was inaltered in both groups; 3) a favourable therapeutic response (global evalution) in three patients of group A, and in three of group D; they represent 40% of the total number of patients studied. For the control of therapeutical effects of the medication the authors suggest a more prolonged period of administration of the medication in hospitalized patients submitted to periodic eletromyographic examinations.