The aim of the present work was to study the effect of hexamethylentetramine, aminazine and analgin preparations, relatively widely used in veterinary practice, on the content of iron, copper and cobalt in blood serum in calves. Under observations were 9 bulls of Shvitz breed (6 experimental, 3 control) of 7-8 months of age, on which 3 series of experiments were carried out. Preparations were applied by intramuscular injections, once in doses (mg/kg body weight): hexamethylentetramine - 12,5 and 50; aminazine - I and 5; analgin - 7,5 and 25. Calves in the control group were administered according to the same method 10 ml of distilled water per animal. The content of trace elements iron, copper and cobalt in blood serum of calves was investigated by atomic absorption spectrophotometry (analyser of ‘Hitachi’ company, model 208) before and 1-3 and b hours after administration of preparations.