Tibet poses particular health hazards to travellers. Almost every visitor is affected by altitude as most of Tibet is over 3000m with plenty of passes over 5000m. For your first two or three days at altitude rest as much as possible and drink plenty of water. A few painkillers should help to relieve any aches and pains and headaches, but more serious problems can develop (see "Basics" section under "China"). Trekkers and anyone travelling long distances in the backs of trucks need to be particularly aware of the dangers of hypothermia . Travellers to Tibet should have rabies immunization before they travel. The dogs here are very aggressive, bites are common and, if you get bitten, Kathmandu is the nearest place stocking rabies serum. A significant number of travellers to Tibet also suffer from giardia , an unpleasant and debilitating intestinal complaint, although there is some controversy over whether it is endemic to the region or brought in from outside. The treatment is Tinadozol or Flagyl which is not reliably available in Lhasa; bring a course along if you can.