BACKGROUND:Aluminum phosphide (AlP) poisoning is common in the developing countries. There is no specific antidote for the treatment of acute AlP poisoning. Early diagnosis of poisoning and outcome predictors may facilitate treatment decisions. The objective of this study was to determine the trend of blood lactate level in acute AlP poisoning to evaluate its role as a prognostic factor. METHODS:This was a prospective study on acute AlP intoxicated patients during one year. Demographic data, clinical and laboratory data on admission, and outcome were recorded in a self-made questionnaire. Blood lactate levels were analyzed every two hours for 24 hours. RESULTS:Thirty-nine (27 male, 12 female) patients were included in the study. The mortality rate was 38.5％. The mean blood pressure, pulse rate, blood pH and serum bicarbonate level were significantly different between the survivors and non-survivors groups. Blood lactate level was significantly higher in the non-survivors group during 8 to 16 hours post ingestion. CONCLUSION:Blood lactate level could be used as an index of severity of acute AlP poisoning.