We report the case of a patient referred to us for mitral and aortic valvular disease with a rheumatic appearance. The unusual macroscopic appearance on valve resection was not compatible with a rheumatic cause. A detailed review of this patient's clinical history (ie, a history of treatment with fenfluramine) suggested an iatrogenic cause, which was confirmed by histology. For the first time, a case of valvular heart disease that deteriorated was discovered 7 years after treatment with fenfluramine, whereas this iatrogenic disease classically resolves after discontinuation of treatment. This case illustrates the need for continuing heart valve surveillance of patients who have used these anorectics.