A large number of visitors apply to Shei-Pa National Park Headquarters for a mountain climbing permit each year. There have been several reports of suspected acute mountain sickness (AMS) in recent years, and serious cases have even resulted in death. Hence, the headquarters reminds visitors to take a gradual approach when climbing high mountains, so that the body will have sufficient time to adapt to the altitude change; do not neglect any symptoms that may be caused by AMS, and remember the mnemonic phrase “3D–Down, Down andDown”, which is the best way to deal with AMS. The main cause of AMS is rapid altitude rise in a short amount of time, but the body cannot adapt to a high altitude environment in time. A mild condition of AMS is similar to a cold and easily overlooked. If you experience headaches, nausea, shortness of breath, and vomiting at altitudes above 2,000 m, they should be viewed as AMS, because if it aggravates into high altitude pulmonary edema or high altitude cerebral edema, it might even result in unconsciousness or death. Symptoms of high altitude cerebral edema include loss of coordination, unstable gait, or change in consciousness.