Systemic anaphylactic reactions to bee or wasp stings are potentially life-threatening. Up to 5% of the population are affected. In the large majority of patients, an insect venom allergy can be diagnosed on the basis of the medical history, skin tests and determination of venom-specific serum IgE antibodies. Sensitization to insect venom (only "positive" test results) and insect venom allergy ("positive" test results and a history of systemic reactions of the immediate type to stings) must be carefully differentiated. Hyposensitization with bee or wasp venom reliably protects almost all patients with systemic sting reactions of the immediate type. Nevertheless, this unproblematic treatment of a potentially life-threatening allergy fails to reach many patients. If a sting challenge or a "field sting" is tolerated during the period of desensitization, treatment can be terminated after three to five years. If, however, the individual patient is at a particular risk, hyposensitization must be continued for a longer period, possibly even life-long.