Phenytoin sodium is an antiarrhythmic drug, and the clinical manifestations of poisoning include: digestive system symptoms, circulatory system symptoms, hematological system symptoms and neurological system symptoms. The symptoms of digestive system include: nausea, vomiting, abdominal distension, abdominal pain and diarrhea, which may be accompanied by blood stool and upper gastrointestinal bleeding in serious cases; the clinical manifestations of circulatory system diseases include: tachycardia, arrhythmia, occasionally accompanied by bradycardia and atrioventricular block; the symptoms of nervous system include vestibular system symptoms, such as vertigo and tremor; the symptoms of hematological system include: leukopenia and granulocytopenia, which may be accompanied by significant anemia in serious cases; finally, there are atypical clinical manifestations such as allergic reactions. Finally, there are atypical clinical manifestations, such as allergic reactions, which are all clinical manifestations of phenytoin sodium poisoning.