Phenobarbital tablets are common psychotropic drugs, commonly used in the treatment of anxiety, insomnia, convulsions, epilepsy and hyperbilirubinemia. 1. Anxiety: Phenobarbital can reduce neuronal excitability, thus playing a sedative role, commonly used in anxiety disorders, as well as hyperthyroidism, hypertension and other diseases caused by restlessness. 2. Insomnia: Phenobarbital reduces neural excitability and can be used to treat insomnia, especially persistent insomnia caused by tension and anxiety. 3. Convulsions: Phenobarbital tablets are commonly used in clinic to fight against convulsions caused by central excitatory drug poisoning or high fever, tetanus, encephalitis, cerebral hemorrhage and other diseases. 4. Epilepsy: Phenobarbital is an important drug for the treatment of grand mal and limited seizures, with poor efficacy in petit mal seizures; and often ineffective in psychomotor seizures. 5. Hyperbilirubinemia: Phenobarbital is a hepatic enzyme inducer, which can enhance the activity of hepatic microsomal glucuronosyltransferase, and promote the combination of bilirubin and glucuronic acid, thus lowering the concentration of plasma bilirubin, and is used for the treatment of neonatal hyperbilirubinemia. Long-term use of phenobarbital may result in folate deficiency, hypocalcemia, and cognitive and memory deficits. Phenobarbital is contraindicated in severe pulmonary insufficiency, cirrhosis, history of hematoporphyria, anemia, history of asthma, uncontrolled diabetes, and allergies. It should be noted that Phenobarbital tablets are prescription drugs and need to be taken under medical supervision. Overdose may cause respiratory muscle paralysis, which can be life-threatening.