Background:Drug rash with eosinophilia and systemic symptoms (DRESS) is a severe drug reaction characterised by rash, eosinophilia and systemic involvement.Main observations:We report a case of DRESS induced by pentoxifylline used for the treatment of severe alcoholic hepatitis, in a patient with longstanding caffeine intolerance. A history of intolerance to caffeine and other methylxanthines is listed as a contraindication to the use of pentoxifylline, yet this precaution is not mentioned in alcoholic hepatitis treatment guidelines.Conclusions: Prescribers should always seek a history of intolerance to caffeine and related compounds prior to use of pentoxifylline, as severe life threatening reactions can occur.