Antibacterial soap may be all washed up. The Centers for Disease Control and Proctor & Gamble sent tests families in Pakistan either ordinary soap or antibacterial soap to determine the effect of hand washing on diarrhea and acute respiratory diseases. Their conclusion: “The incidence of disease did not differ significantly between households given plain soap versus antibacterial soap.” Uh-oh.

Also, alcohol-based mouthwashes may not kill germs that cause bad breath because the alcohol dries out the mouth. There’s not enough saliva to help wash away any bad breath bacteria. (Bad breath is caused by food stuck between your teeth and the accumulation of bacteria on the back of your tongue.)

Breathing recycled air on airplanes is not what makes passengers sick. It’s inhaling the effluvia from seatmates who spew mucus droplets when they cough, sneeze, or even yawn.