Surgery and its sequelae.
D005743:Gastrectomy; D005763:Gastroenterostomy; D006801:Humans; D010437:Peptic Ulcer / Q000601:surgery*; D010438:Peptic Ulcer Hemorrhage / Q000601:surgery; D010439:Peptic Ulcer Perforation / Q000601:surgery; D011183:Postoperative Complications / Q000209:etiology; D012008:Recurrence; D014628:Vagotomy