From 1969 to 1984, we treated 178 patients with acute gastric anisakiasis caused by gastric mucosal penetration of the Anisakis larvae. Because the larvae of Anisakis can always be observed by endoscopy and removed with biopsy forceps, early performance of endoscopy is highly recommended for patients in whom acute gastric anisakiasis is suspected and for those who have eaten raw fish within 12 hours before onset of the gastric symptoms. Endoscopic removal is essential to relieve the intolerable pain; after relief, the administration of antacids will repair the damaged gastric mucosa. Ulcer formation is rare.