Diastat is a brand name for the medication diazepam rectal gel, which is used to treat prolonged seizures, also known as status epilepticus, and acute repetitive seizures. Diazepam belongs to a class of drugs called benzodiazepines, which work by enhancing the effects of a neurotransmitter in the brain called gamma-aminobutyric acid (GABA). GABA is an inhibitory neurotransmitter, which means that it helps to slow down or inhibit the activity of nerve cells in the brain. By enhancing the effects of GABA, diazepam can help to reduce seizure activity in the brain and prevent further seizures from occurring.