Altitude Sickness, often known as 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 elevations above 3,000 meters. The initial symptoms of AMS are as following:

• Nausea, vomiting
• Loss of appetite
• Insomnia / sleeplessness
• Persistent headache
• Dizziness, light headedness, confusion,
• Disorientation, drunken gait
• Weakness, fatigue, lassitude, heavy legs
• Slight swelling of hand 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 problems can occur which can even cause death sometimes within a few hours, the only cure for the Altitude Sickness is to descend to a lower elevations immediately. Acclimatization by ascending to no more than 300 to 500 meters per day above 3,000 meters and the proper amount of rest are the best methods for preventions of AMS.

Literatures and pamphlet published by Himalayan Rescue Association consists of detailed information on AMS. The Central Immigration Office and all trekking agencies in Katmandu distribute this pamphlet free of Cost. Since these medical also give information on the list of suggested documents supplies for trekkers it is a compulsory item for every trekkers' medical kit.