Researchers at Aberystwyth University in the UK said habitual handshaking allows movement of germs between people, and can help spread contagious illness.
Using rubber gloves and a thick layer of E coli, scientists exchanged handshakes, high fives and fist bumps.
They found that transfer of potentially disease-causing bacteria is highest during a handshake.
Dr Dave Whitworth, Senior lecturer at Aberystwyth University, and PhD student Sara Mela carried out the research, dipping a glove into a bacterial broth before gingerly extending a hand.
They found that a high dose of bugs were passed on during a handshake.
This was reduced by over half in the high-five, and germ transfer was a whopping 90 per cent lower when bumping fists.
The hygienic nature of the fist bump may be due in part to its speed (typically much quicker than a first-rate handshake) but also because there is a smaller area involved.
Direct contact is needed for most microbes to move, so minimising the parts of the hand that touch gives bacteria less chance to spread.
The study was published in the American Journal of Infection Control.
