Background Rashes are the most common adverse reaction to drugs. Our aim is to describe (i) the prevalence of cutaneous adverse drug reactions in hospitalised patients over a 1-year period in our hospital; (ii) the variety of cutaneous drug reactions; (iii) the characteristics of patients with cutaneous drug reactions and (iv)the drugs implicated. Methods A retrospective analysis of all adverse drug reactions from the pharmacists’ database from January to December 2003 was conducted. Patients’ records were reviewed to extract demographic data, drug implicated, route of administration, drug allergy history, type of cutaneous reaction, severity and presence of underlying chronic disease. Results Sixty-five patients met our inclusion criteria, giving an estimated prevalence of 1.8/1000 among hospitalised patients. The cases were mostly from the general medicine department (64.6%), with a slight male predominance (males, 53.8%; females 46.2%). Cutaneous adverse drug reactions were more common in the Malay population (32.3%). The mean age was 41.6 years (range, 13 to 85 years). The main drugs implicated were antibiotics (49.2%), mainly penicillins and cephalosporins, and non-steroidal anti-inflammatory agents (16.9%). Urticarial (46.1%) and generalised maculopapular eruptions (40.0%) were the most common patterns encountered. Others included Stevens-Johnson syndrome/toxic epidermal necrolysis (7.7%), drug reaction with eosinophilia and systemic symptoms (1.5%) and erythroderma (1.5%). 29.2% of cases were considered to be severe. There were no deaths. 44.6% had an associated chronic disease and 24.6% had a previous documented drug allergy. Conclusion Antibiotics and NSAIDs were the major drugs involved. The commonest cutaneous manifestations were urticarial and maculopapular eruptions. A high proportion of reactions were considered severe and almost one-quarter had a previous drug allergy.