Xanax is a benzodiazepine prescribed to treat anxiety disorders. It is illegal and dangerous to purchase Xanax online without a valid prescription from a licensed doctor. Doing so increases risks of abuse, addiction, receiving expired or counterfeit medications from unlicensed online pharmacies. While it is possible to purchase Xanax online legally with a valid prescription, care must be taken to ensure the online pharmacy is properly licensed and prescription information is verified. Abruptly stopping Xanax can worsen withdrawal symptoms, so any changes in dosage should be done gradually under a doctor's supervision.