If you visit the Himalayan Mountains or the Qinghai-Tibet Plateau, try to ascend gradually to allow your body to adjust to the high altitude. You should also use sunblock as the risk of sunburn is greater at high elevations. What preventative measures can I take against sickness?
Wash your hands regularly
Only drink bottled or boiled water, or use your own purification methods.
Keep your feet clean and dry. Don't go barefoot.
Use latex condoms to reduce the risk of HIV and other sexually transmitted diseases.