The objective of this study was to demonstrate the clinical profiles of Stevens–Johnson syndrome (SJS) in Thai patients, and to compare those clinical features between younger and older patients. Medical records of all patients with SJS who were admitted to Srinagarind Hospital Medical School, Khon Kaen, Thailand, from January 2002 to December 2014 were reviewed. Epidemiological features, etiologies, treatment and clinical outcomes were collected. There were 45 patients with SJS during the 10-year period. Females were the majority (57.8%) and the median age was 49 years. Hepatitis was the most frequent complication (67.5%). Phenytoin (15.6%), sulfonamide drugs (15.6%) and allopurinol (13.3%) were implicated as leading causes of SJS. Steroids were prescribed in 37 cases (82.2%). The mortality rate was 4.4%. Comparing older patients to younger patients, allopurinol appeared to be the main instigating drug to develop SJS with an odds ratio of 5.6 (95% confidence interval, 2.8–10.6). In conclusion, clinical features of Thai patients with SJS were similar to other reports. Allopurinol had the strongest association with SJS in older patients as compared to the younger ones.