Four young adults poisoned with thallium contained in maliciously contaminated marzipan ball candy are reported from the New York City Poison Center, and East Carolina University School of Medicine, Greenville, NC. Gastrointestinal symptoms, including diarrhea, vomiting, abdominal cramps, and constipation, and pleuritic chest pains developed on the second day, and painful paresthesiae of hands and feet on the third day. Weight bearing caused pain in the soles of the feet, so that walking was avoided. Stroking the back of the hands elicited severe pain. Radiographs of the candies showed metallic densities, and atomic absorption spectroscopy measurement of thallium content was 4g/100g candy. Radiographs of the abdomen on the third day were negative for radiopaque thallium. Hypertension and tachycardia developed on day 4 to 8, and alopecia onset began on day 8 to 15. Treatment consisted of prussian blue (2g 3x/d orally) to bind enteric thallium, activated charcoal orally, potassium chloride infusion, and iv morphine for pain. All patients recovered without sequelae within one month. 
COMMENT. Gastrointestinal symptoms followed closely by painful paresthesiae of extremities are the early diagnostic manifestations of thallium poisoning. Alopecia is a late sign. The authors advocate early treatment with prussian blue. Thallium is radiopaque and radiographs of poisoned food may demonstrate metallic densities.