Thanks to stories like the play Arsenic and Old Lace, familiarity with arsenic poisoning is widespread. Few have even heard of chronic arsenic toxicity or arsenicosis, which initially is a dermatological problem. Patients present with mottled hypopigmentation and hyperpigmentation, known as “raindrops on a dusty road,” and palmoplantar keratoses as well as multiple squamous cell and basal cell carcinomas. Later, internal cancers can develop, most often involving the lungs and bladder. Only inorganic forms of arsenic are implicated in arsenicosis, and systemic features vary with the arsenic salt; for example, in Taiwan, severe peripheral vascular disease known as “black foot disease” develops. No arsenicosis developed when organic arsenic compounds like Salvarsan were used to treat syphilis.