A case of acute thallium poisoning presenting with sudden abdominal pain, paraesthesiae and irritability is described. The peripheral nervous system was later affected along with loss of hair and the development of streaks (Mee's lines) on the nails of the hands and feet. The diagnosis was established by thallium assays of blood and urine. Thallium was undetectable in the blood by day 70. The manifestations cleared in six months with symptomatic treatment only. We review the characteristics and differential diagnosis of thallium poisoning and stress the importance of a high index of clinical suspicion.