Amitraz, a formamidine insecticide and acaricide used in veterinary practice, presents side effects in humans related to its pharmacological activity on alpha 2-adrenergic receptors. There is little information available in the literature about the toxicology of the product in man and the treatment of this poisoning. In this report, the clinical and laboratory features of amitraz poisoning in two patients by a veterinary formulation also containing xylene are presented. The major clinical findings were unconsciousness, drowsiness, respiratory failure requiring mechanical ventilation, miosis, hypothermia and bradycardia. The laboratory findings were hyperglycemia, hypertransaminasemia and increased urinary output. Supportive management of this poisoning in humans is suggested in only a few articles and there is no specific antidote for the subsequent possible pharmacological effects of amitraz. In our two cases, we performed supportive treatment such as mechanical ventilation, atropine, gastric lavage, active carbon, oxygen and fluid administration. We concluded that the basic approach to the patient with amitraz poisoning, including initial stabilization to correct immediate life-threatening problems, treatment to reduce absorption and measures to improve elimination of the toxin, is effective.