Switzerland is part of the Schengen agreement so if you're from one of the five European members, you will not need anything special to enter the country. Visas are also not necessary for citizens of the US, Australia or Britain for stays up to 90 days. More info on visa requirements can be found at the Federal Office for Migration website (http://www.bfm.admin.ch/bfm/en/home.html).
Health and Safety
Travel in Switzerland is generally trouble-free even in the bigger cities. However, the usual precautions should be taken, such as keeping valuables in a safe, out of sight and securing your bag, as petty crimes such as pick pocketing do occur.
There are no specific health risks in Switzerland and the main issue you may face is injuries from outdoor activities. Those heading into the mountains should be aware that the weather can change quickly and unexpectedly. Always be prepared even if it is sunny when you head out. Sturdy shoes, waterproof jackets and walking sticks are highly recommended, as are small supplies of food and water.
Driving in the winter can also be treacherous, so make sure your vehicle has snow chains, a legal requirement in Switzerland. In the mountains, drivers need to be careful of sudden weather changes and black ice, especially at night.
Switzerland has world-class medical facilities and hospitals; however, these are limited primarily to the big cities. Healthcare costs can quickly add up, so be sure to have proper travel insurance prior to departing.