A 17 years old girl experienced an anaphylactic reaction of urticaria, dyspnea, syncope and hypotension while riding a bicycle 55 minutes after eating shellfish Lapas shellfish which was a-like Sulculus Supertexta (SS). She recovered within several hours after the emergency treatment. Another attack occurred 3 months later while she was running with a dog 30 minutes after eating shellfish (Turbo Cornutus; TC). RAST scores were 4 for Lapas and 2 for TC. RAST inhibition test by ELISA showed a high crose-reaction between keyhole limpet hemocyanin (KLH) and Lapas, and between KLH and TC, while the cross reaction between Lapas and TC was low. Gel chromatography with sephacryl G-200 revealed that both Lapas and TC had several allergens with different molecules which were detected by ELISA. Exercise challenge produced an immediate fall of FEV1 and a significant increase in plasma histamine levels for 45 minutes.