Acute Mountain Sickness (AMS) is particularly a important medical consideration while trekking in Nepal. Altitude sickness means the effect of altitude on those who ascend too rapidly to elevation above 3000 m.

• Nausea, vomiting
• Loss of appetite
• Insomnia / Sleeplessness
• Persistent headache
• Dizziness, lightheadedness, confusion,
• Disorientation, drunken gait.
• Weakness, fatigue, lassitude, heavy legs.
• Slight swelling of hands and face
• Breathlessness and breathing irregularity
• Reduced urine output.

These symptoms are to be taken very seriously. In case of appearance of any of the above symptoms any further ascent should be reconsidered, otherwise more serious problem can occur which can even cause death sometimes within a few hours. The only cure for the altitude sickness is to descend to lower elevations immediately and it has no other cure or substitute. Acclimatization by ascending to no more than 300 to 500 meters per day above 3000 meters and the proper amount of rest are the best methods for prevention of AMS. Literature and pamphlet published by "Himalayan Rescue Association" consists of detailed information on AMS .The central Immigration office and all trekking agencies in Kathmandu distribute this pamphlet free of cost. Since these documents also give information on the list of suggested medical supplies for trekkers it is a compulsory item for every trekkers' medical kit.