Acute, sudden irritation of the gastric mucosa. It may be caused by ingestion of toxic substances such as alcohol or poisons or overuse of NSAIDs. Symptoms include anorexia, nausea, epigastric pain, vomiting, thirst, and, when patients become dehydrated, prostration. Therapy includes antacids, H2 receptor blockers, or proton pump inhibitors (all of which reduce gastric acidity). Antibiotics treat bacterial and endotoxic infections.