Researchers say more people prefer red and pink tablets over other colors, an indication that color and shape can affect how people take the drug.

R.K. Srivastava and colleagues at the University of Bombay found 450 of the 600 people they surveyed used the color and shape of their tablets as a barometer to consume the drugs. A tenth of those who surveyed said that orange-colored tablets are sour, while 11 percent say white or blue tablets taste bitter.

Irrespective of the ingredients in the tablet, a yellow pill is salty while 14 percent of people say pink pills taste sweeter than red tablets.

"Patients undergo a sensory experience every time they self-administer a drug, whether it's swallowing a tablet or capsule, chewing a tablet, swallowing a liquid, or applying a cream or ointment," the researchers say in a statement. "The ritual involving perceptions can powerfully affect a patient's view of treatment effectiveness."

The research is published in the International Journal of Biotechnology.