A "benzo" is a colloquial term for benzodiazepines, which are a class of drugs that work as central nervous system depressants. They have a core chemical structure consisting of a benzene ring fused to a diazepine ring. Benzodiazepines are prescribed for various medical conditions, including anxiety disorders, insomnia, seizures, muscle spasms, alcohol withdrawal, and as premedication for medical or dental procedures. They work by enhancing the effect of the neurotransmitter gamma-aminobutyric acid (GABA) at the GABA-A receptor in the brain, which produces sedative, hypnotic (sleep-inducing), anxiolytic (anti-anxiety), anticonvulsant, and muscle relaxant effects. Benzodiazepines are categorized by their duration of action into short, intermediate, or long-acting types. Short-acting ones are often used for insomnia, while longer-acting are preferred for treating anxiety. While benzodiazepines are effective for their intended uses, they carry risks such as potential addiction, tolerance, withdrawal symptoms, and side effects like drowsiness, confusion, and impaired coordination. Hence, they are usually prescribed for short durations under careful medical supervision. Common examples include diazepam (Valium), alprazolam (Xanax), lorazepam (Ativan), and clonazepam (Klonopin) among others. In summary, a "benzo" is essentially a benzodiazepine drug, used medically mainly to relieve anxiety, induce sleep, relax muscles, and control seizures, but they need to be used cautiously due to their potential for dependence and side effects.