<prompt> A middle aged man presents with paraesthesia of hand and feet. Examination reveals presence of Mees lines in the nails and rain drop pigmentation in the hands; The most likely causative toxin for the above mentioned symptoms is :LeadArsenicThalliumMercury  <response>: Mees lines in the nails and rain drop pigmentation of skin are characteristic of arsenic poisoning. Treatment of choice - freshly precipitated hydrated ferric chloride. Reference The Synopsis of FORENSIC MEDICINE and Toxicology 29th Edition 