Symptoms of acute thallium poisoning include gastrointestinal symptoms such as nausea, vomiting, light mouth, abdominal pain, and diarrhea. Symptoms of neurological damage mostly appear after 2 to 5 days of acute thallium poisoning. They mainly include limb neuralgia, muscle weakness, etc. Headache, drowsiness, neurological disorganization, hallucinations, convulsions, delirium, coma, etc. may occur. Chronic thallium poisoning is characterized by ataxia, sensory abnormalities, muscle weakness and muscle atrophy. In addition, alopecia is an obvious manifestation of thallium poisoning, which usually appears about 3 weeks after acute poisoning and manifests as patchy baldness or total baldness, and there may be loss of eyebrows. Alopecia in thallium poisoning is generally reversible and can recover several months after the disease. Patients with thallium poisoning may have sinus tachycardia, angina pectoris, anemia, and lymphopenia. Thallium poisoning patients may also have optic nerve damage, manifested as optic neuritis, optic nerve atrophy, vision loss or even blindness. Patients with severe thallium poisoning may have pulmonary edema, respiratory failure, shock, etc., and may die within a few weeks.