Acute gastroduodenal injury after ingestion of diluted herbicide pendimethalin

The herbicide, pendimethalin, is used worldwide, but its acute toxicity is not yet widely known. There have been some reported acute pendimethalin poisoning cases in humans and most of them intentionally ingested the concentrated formulation. We describe a 73-year-old man who developed corrosive gastroduodenal injury after accidental ingestion of the diluted (300 times with water) pendimethalin formulation. He had a history of reflux oesophagitis and had been taking omeprazol (10 mg/day) for a year. He consumed alcohol two hours after the accidental ingestion and then had nausea and epigastric pain. Endoscopy performed three days post-exposure revealed gastroduodenal injury. As he had consumed alcohol every day for years and had no history of gastroduodenal ulcer, the accidental ingestion may be associated with this injury. He was successfully treated by increasing his dosage of omeprazol (20 mg/day) for two weeks. This case indicates that ingestion of a small quantity of pendimethalin can provoke gastroduodenal injury.