Clenching of the teeth in bed at night could be a convulsive seizure, seen in epilepsy, or it could be caused by low blood calcium. Primary epilepsy includes primary and secondary epilepsy. The exact etiology of primary epilepsy is unclear, and is mainly treated with antiepileptic drugs, commonly used are carbamazepine, sodium valproate, phenytoin sodium, clonazepam, ethosuximide, levetiracetam, oxcarbazepine, gabapentin, and lamotrigine. Secondary epilepsy generally has a clear etiology and is mainly treated with the appropriate etiology. Common etiologies include cranial tumors, cerebral hemorrhage, cerebral infarction, encephalitis, cranial trauma, and abnormal brain cortex development. A part of systemic diseases such as hyperthyroidism and diabetes mellitus, patients may also have seizures. If low blood calcium is considered to be the cause, patients may also have leg cramps, which are mainly treated with commonly used drugs such as calcium-in-calcium, calcium erginate and calcium gluconate.