In a prospective five-year follow-up study of 289 consecutive patients subjected to antrectomy and gastroduodenostomy with or without vagotomy, 130 patients underwent gastroscopy. Gastric mycosis was present almost exclusively in patients subjected to combined antrectomy and vagotomy (36%). Gastric acidity seemed to be of only minor or no importance in the development of the mycosis. The residual volume in the gastric remnant was significantly higher in patients with gastric mycosis. The impaired emptying of the gastric remnant is most likely a vagotomy effect and may be the main reason for the development of gastric mycosis. A simple but effective method was developed to evacuate gastric yeast cell aggregates. Gastric mycosis seems to give rise to only slight symptoms, mainly nausea and foul-smelling belching, whereas the reflux of duodenal contents that often occurred in combination with gastric mycosis was more likely to cause gastritis and substantial discomfort.