A patient who developed chronic salicylism associated with salicylate therapy for treatment of juvenile rheumatoid arthritis is described, and the clinical presentation and treatment of chronic salicylism are reviewed. A 5 1/2-year-old boy was receiving aspirin 150/mg/kg/day for treatment of juvenile rheumatoid arthritis. While on salicylate therapy, the patient developed tachypnea and became increasingly hyperthermic, lethargic, and disoriented. The patient developed a maculopapular rash, weakness, and a decreased level of consciousness during the 11 days before admission to the hospital. Physical examination and laboratory determinations revealed that the patient had hypoprothrombinemia, hypoglycemia, and severe hepatic encephalopathy secondary to long-term salicylate toxicity. The patient was treated for hypoglycemia, electrolyte imbalances, thrombocytopenia, and anemia and was discharged after 24 days. Diagnosing chronic salicylism with hepatic dysfunction was difficult because the symptoms are similar to those of stage I to stage II Reye's syndrome. Liver enzymes, including aspartate aminotransferase (also called SGOT), alanine aminotransferase (also called SGPT), alkaline phosphatase, and lactate dehydrogenase, may be elevated in juvenile arthritis patients with hepatic dysfunction. Liver dysfunction usually improves when salicylate therapy is discontinued. Supportive therapy should always be used in symptomatic patients. Children on long-term, high-dose salicylate therapy should be monitored closely, and baseline liver function tests should be performed. The clinical effectiveness of administering sodium bicarbonate in attempts to alkalinize urine and increase salicylate elimination is controversial. In patients with juvenile rheumatoid arthritis who develop chronic salicylism, careful analysis of the patient's medication history, laboratory values, and clinical presentation are necessary to rule out Reye's syndrome.