Acetylsalicylic acid (ASA) intoxication is potentially lethal. After ingestion, AAS is rapidly transformed into salicylic acid that dissociates into an hydrogen ion plus salicylate. Salicylate is the main form of AAS in the body and produces multiple alterations. Initially, the stimulation of the ventilatory center promotes a respiratory alkalosis. Then, the mitochondrial dysfunction induced by salicylate, will generate a progressive metabolic acidosis due to the accumulation of ketoacids, lactic acid and dicarboxylic acids among others. Another alterations include hydro electrolytic disorders, gastrointestinal lesions, neurological involvement, ototoxicity and coagulopathy. The correct handling of acetylsalicylic acid intoxication requires an thorough knowledge of its pharmacokinetics and pharmacodynamics. Treatment consists in life support measures, gastric lavage, activated charcoal and urinary alkalization to promote the excretion of salicylates. In some occasions, it will be necessary to start renal replacement therapy as soon as possible.