The authors describe a clinical case of rhinitis and asthma in an angler after exposure to antigenic material released from larvae of fly, commonly used by anglers as bait. The common names of these larvae are "blue bottle", "green bottle" and "grey bottle". The patient was usually in good health, free from allergic diseases and free from asthmatic attacks when far from exposure to the baits. Spirometric evaluation revealed a fall of 21% in VEMS after challenge with antigen. Skin test (prick) with an extract obtained from the baits and RAST were strongly positive. By avoidance of exposure to antigen obtained changing type of bait, the asthmatic attacks completely disappeared. The authors discuss the clinical, diagnostic and preventive aspects of this allergic syndrome, and deal with the taxonomy of the insect.