(NBC NEWS CHANNEL) The Dalai Lama and President Obama do it... not to mention the cooler kids among us.
Now experts are suggesting the "fist bump" may be more hygienic than handshakes when doctors greet their patients.
"We're all just little petri dishes walking around,” says Dr. Mary Lou Manning with the Association for Professionals in Infection Control and Epidemiology.
Dr. Manning says our hands are covered with bacteria -- most of it is perfectly safe. But there are also potentially dangerous staph and viruses like the flu. "For most patients, it won't be a problem, but for some, it will, and you just never know who those patients might be."
Hands are notorious for passing along germs because we touch everything with them -- including our mouths and eyes.
A new study finds the handshake transmits double the amount of bacteria a high five would. The fist bump transmits even fewer.
Still -- some experts say a hands-off approach may be safest for patients.
"Rather than replace the handshake with something else that has contact, probably the better approach to keep patients safe is really not to do it at all,” Dr. Manning says.
The study is from Aberystwyth University in the UK, and is published in the American Journal of Infection Control.
Reported by: Erika Edwards, NBC News for NBC NewsChannel