Blood samples will be obtained from study patients for the analysis of inflammatory cytokines and nitrotyrosine. Blood samples will be obtained at the time of blood sampling for the routine clinical management of the APAP overdose patient. Patients who are hospitalized will have study blood samples drawn at the time daily blood samples are obtained. The sampling will continue daily until the patient is discharged. In addition to blood sampling the following data will be collected: age, gender, race, circumstances of the ingestion, dose of the ingestion, treatment for the ingestion, concomitant therapy, medical history and cigarette use.