The venoms of hymenopterans are complex mixtures of various organic compounds, proteins, and peptides that can cause local pain, inflammation, itching, irritation, and moderate to severe allergic reactions. Of all venoms, that of the honeybee Apis mellifera is the best studied. It is rich in enzymes and peptides, but also contains histamine, serotonin, dopamine, noradrenaline, and polyamines. Among the enzymes, phospholipase A2 (responsible for the breakdown of membrane phospholipids), hyaluronidase (breakdown of hyaluronic acid contained in the intercellular matrix), acid phosphatase (removal of the phosphate group from organic phosphates), etc., are notable. Among the peptides, melittin (lytic polypeptide), apamin (neurotoxic peptide), and mast cell-degranulating peptide (MCD) are well known. The bee venom enzymes are proteins with a molecular mass between 15.0 and 50.0 kDa. Phospholipase A2 (15.0–16.0 kDa) accounts for the largest proportion at about 12%. In addition to causing edema, it also has cardiotoxic, neurotoxic, myotoxic, anticoagulant, and other effects, and is a strong allergen. Phospholipase breaks down the phospholipids of cell membranes into lysophospholipids and long-chain fatty acids, creating pores in the cell membrane and thereby destroying the cell. Numerous studies have demonstrated a synergistic reaction between phospholipase A2 and melittin (see below). The result is hemolysis (destruction of red blood cells). Hyaluronidase is an enzyme responsible for the breakdown of hyaluronic acid and chondroitin sulfate, substances found in connective tissue and intercellular tissue. Hyaluronidase makes the environment of the stung tissue more spongy and more accessible to the venom. It is therefore also referred to as a “venom spreading factor.” The molecular weight ranges from 30.0–60.0 kDa. Acid phosphatase or phosphomonoesterase makes up about 1% of the dry matter of bee venom. It removes phosphate groups from various organic substrates and is active at low (acidic) pH values. Other enzymes found in bee venom as well as in the venoms of other hymenopterans include alpha-glycosidase (0.6% of dry weight), lysophospholipase, various esterases, lipases, etc. Lipases are thought to be involved in the processes of cell lysis (disintegration of a cell). The venoms of hymenopterans also contain proteases. It is suspected that they cause moderate necrosis. The best studied is the protease of the bumblebee (Bombus), which is responsible for some severe allergic reactions. These arise through the interaction of mast cells with immunoglobulin E (IgE). A cascade of mediators is triggered, including histamine, leukotrienes, platelet-activating factors, enzymes, peptides, etc., which cause persistent local inflammation. In rare cases, this reaction can lead to cardiorespiratory depression, systemic anaphylactic shock, and death. In most cases, stings from representatives of the Hymenoptera are mild. Typically, they are accompanied by pain, local inflammation, and itching, which subside after a few hours.