Antivenom is the most effective method currently available for the treatment of poisonous snake bite. Allergic reactions to antivenom have been reported in the past. Here we shared a case of allergic re-actions to antivenom in an old male patient who was bitten twice by the same snake (probably same one) at the same biting site within a month whereas the patient did not show any allergic disorder in the first bitten. Envenomations twice in a short period time by the same kind of snake are very rare. Physician should be alert to the occurrence of allergic reactions in treating this type of patients with antivenom. The skin allergy test has a certain value in predicting the allergic response before the second use of antivenom. Desensitization may reduce the incidence of allergic reactions, but this is insufficient. Rather than non-IgE-mediated immediate hypersensitivity, patients receiving the second treatment of antivenom may develop IgE-mediated immediate hypersensitivity. Once happened, the antivenom treatment should be stopped promptly and anti-allergy treatment should be given immediately.