Stings by insects of the order Hymenoptera cause systemic, sometimes life threatening allergic reactions in 1 - 5% of the population in Europe and North America. Responsible for these reactions is an IgE mediated sensitization to proteins of the venoms injected during the stings of social Hymenoptera species, mainly the honey bee (Apis mellifera), vespids like Vespula sp, Polistes sp. and ants, in southern US and central America Solenopsis invicta and in Australia Myrmecia pilosula. The venoms of these insects are composed of low molecular weight substances like biogenic amines, cytotoxic and neurotoxic peptides like melittin, apamin, MCD-peptide and mastoparan, and proteins, mostly enzymes like phospholipase A and hyaluronidase, which are major venom allergens. Immunotherapy with Hymenoptera venoms has been shown to protect 80 to over 95% of patients with a history of systemic allergic sting reaction from further systemic reactions after re-stings. The procedure, safety and efficacy of this treatment and the immune mechanisms involved are discussed. Since ancient times honey bee venom has been used for the treatment of chronic inflammatory disease, especially arthritis. Anti-inflammatory effects of bee venom have been documented in animal experiments. Most clinical studies suggest an antiinflammatory effect as well, but are uncontrolled. The only few controlled studies could not confirm efficacy of treatment with bee venom so far.