Acetazolamide is a medication commonly used to prevent and treat acute mountain sickness (AMS). It works by increasing breathing rate and promoting mild metabolic acidosis, which helps the body take in and use oxygen more efficiently at high altitudes. The drug also acts as a mild diuretic, reducing fluid buildup that can contribute to symptoms like headache and swelling. When taken at doses of 125–250 mg twice daily, it can speed up acclimatization and relieve mild AMS symptoms. It is especially useful for travelers who must ascend quickly or have a history of altitude sickness.