Seventeen patients who had been admitted to hospital for wasp/bee sting were studied. Mild pyrexia was encountered in 7 patients, rash/urticaria in 3, angioneurotic oedema in 2, oliguria in 2, microscopic haematuria and albuminuria in 3, transient hypotension in 1. However, there were frequent elevations of serum glutamic-oxaloacetic transaminase (9 out of 17 patients), serum creatine phosphokinase (14 out of 17 patients) and serum lactate dehydrogenase (8 out of 14 patients), indicating presence of damage to muscle fibres. This was confirmed by the histological findings of a muscle-biopsy from the most severe case. Elevation of serum glutamic-pyruvic transaminase was found in 6, and elevation of serum isocitrate dehydrogenase in 5 out of 14 patients, suggesting presence of liver damage. The above enzyme elevations appeared short-lived except in the clinically most severe patient (case 9) who developed acute tubular necrosis. All patients except the latter suffered no clinical sequelae and there was no correlation between their clinical condition and the presence or degree of elevations of serum enzymes.