ABSTRACT Background: Analysis of blood gases and acid-base status is an essential tool in assessment of ill patients in the emergency setting. However, the role of acid-base disturbance on survival of acutely poisoned patients has not been thoroughly investigated. Objective: To evaluate the role of arterial blood gases (ABG) and serum lactate level for early detection of the severity of toxicity and prediction of death in acutely poisoned patients. Patients and methods: The current study is a prospective study that was done on 100 of acutely poisoned patients by drugs and toxins with acid base disturbances effect. They were admitted to Ain-Shams Poison Control Center, during the period from January 2019 to the end of December 2019. Results: Results of the current study revealed that 47.8% of dead patients suffered from metabolic acidosis and respiratory acidosis, 30.4% of them, were with metabolic acidosis, 13% of them were with respiratory acidosis, and 8.7% of them, were with metabolic acidosis and respiratory alkalosis. According to ROC curve analysis serum lactate level can be used as a predictor of mortality as serum lactate level with cut off ˃ 1.45 had sensitivity of 91.3%, specificity 29.8% and NPV 93.6% with excellent diagnostic characteristic ( accuracy rate 84.6%). Conclusion: The study concluded that ABG and serum lactate level can be used as simple predictor tools of the severity of toxicity and prediction of death in acutely poisoned patients.