Varying observations have been made concerning the use of aspirin (ASA) and/or intravenous immunoglobulin (IVIG) in the prevention of coronary artery aneurysm (CAA) in children with Kawasaki disease. A meta-analysis of published articles on the subject was conducted to evaluate the reported efficacy of these therapies. All published studies in all languages from 1967 through 1993 obtained from MEDLINE and EMBASE were considered, and a defined set of inclusion and exclusion criteria selected the studies for analysis. These studies were grouped based on whether the children in the studies received: (1) ASA alone, (2) low IVIG (< or = 1 g/kg) and ASA, (3) high IVIG (> 1 g/kg) and ASA, (4) single IVIG (> 1 g/kg) and ASA, (5) high IVIG and low ASA (< or = 80 mg/kg), or (6) high IVIG and high ASA (> 80 mg/kg). Studies that satisfied the test for homogeneity were subjected to further analysis. The best estimate of the true proportion of CAA as well as the 95% confidence interval for each group were calculated at 30 and 60 days. Hypothesis testing was conducted to determine the statistical significance of the calculated difference in each compared treatment group. The best estimate of true proportion of CAA and the 95% confidence interval in each group at 30 and 60 days were: (1) ASA group, 30 days, 22.8% (20.6%, 25%); 60 days, 17.1% (13.6%, 20.7%); (2) low-IVIG group, 30 days, 17.3% (14.3%, 20.2%); 60 days, 11.1% (8.7%, 13.6%); (3) high-IVIG group, 30 days, 10.3% (8.3%, 12.3%); 60 days, 4.4% (2.8%, 6%); (4) single-IVIG group, 30 days, 2.3% (0.5%, 4.2%); 60 days, 2.4% (0.5%, 4.2%); (5) high-IVIG-low-ASA group, 30 days, 13% (9%, 17%); 60 days, 4.8% (2.3%, 7.4%); and (6) high-IVIG-high-ASA group, 30 days, 9.1% (6.9%, 11.4%); 60 days, 4% (2%, 6.1%). The incidence of CAA both at 30 and 60 days was significantly lower in low-IVIG than in ASA and in high-IVIG than in low-IVIG groups. Also, the incidence was lower in the single-IVIG than in the high-IVIG group, but this was noted at 30 days and not at 60 days. There was no statistically significant difference in the incidence of CAA both at 30 and 60 days between the high-IVIG-low-ASA and high-IVIG-high-ASA groups.