Diazepam (Valium) is a benzodiazepine. It’s used to treat symptoms of anxiety and alcohol withdrawal. It can also treat certain types of muscle spasms and seizures. Diazepam (Valium) comes as a tablet and liquid solution. It’s taken by mouth, typically 2 to 4 times daily. Some common side effects of diazepam (Valium) include sleepiness, dizziness, and weakness.