Among the PHT-induced SJS/TEN patients, 20.00 % carried the HLA-B*15:02 while 14.86 % of the PHT -tolerant controls carried this allele. The prevalence HLA-B*15:02 in the cases and controls was not significantly different among the case and the control groups suggest that HLA-B*15:02 may not be a valid genetic marker for screening Thai patients who at higher risk of PHT-induced SJS/TEN.