Acute mountain sickness (AMS) is an ilness, that occurs in non-acclimatized individuals after rapid ascent to high altitude, typically above 2,500 metres (8,000 ft). The main causes of the AMS are: reduced air pressure and lower oxygen levels at high altitudes. The early symptoms of AMS are non-specific such as: headache, anorexia, nausea, vomiting, fatigue, dizziness, and sleep disturbance, but not all need to be present at one time. It is very important to recognise the early symptoms of AMS and to start the treatment, because untreated AMS can progress to the life‐threatening: high altitude cerebral edema (HACE) and high altitude pulmonary edema (HAPE). Treatment of AMS consists of stabilization of the patient conditon, descent to lower altitude, oxygen therapy and administering acetazolamide and dexamethasone. The aim of this study was to evaluate the significance of the proper acclimatization, use of the acetazolamide and dexamethasone in prevention of acute mountain sickness (AMS).Proper acclimatization, use of the acetazolamide and dexamethasone are highly effective in prevention of occurrence and reducing the symptoms of acute mountain sickness (AMS). Pharmacological prophylaxis is not necessary in low-risk situations but should be considered in addition to gradual ascent for use in moderate- to high-risk situations Acetazolamide should be strongly considered in climbers and travelers at moderate or high risk of AMS with ascent to high altitude. Dexamethasone can be used as an alternative in individuals with a history of intolerance of or allergic reaction to acetazolamide. In rare circumstances (eg, military or rescue teams that must ascend rapidly to and perform physical work at >3500 m), consideration can be given to concurrent use of acetazolamide and dexamethasone.