AbstractThis paper describes in detail the dermatological, medical, and laboratory findings of patients poisoned with PCBs and related compounds in Taiwan. Together with their symptoms, their skin lesions as well as their hematological, immunological, and other clinical features are explained. A grading of their clinical severity was tried, and its possible association with PCB concentrations in their blood was examined but could not be demonstrated. Various treatments have been applied but without notable success. Even so, a follow‐up study of patients one year later showed that about 38% of patients were somewhat clinically improved, while 54% were not altere