People habituated to biting their cheeks will find white residue in their mouth, which is nothing but excess keratin produced ...

E-cigarette users had similar changes to the DNA in specific cheek cells as smokers, according to a new study that provides some insight into the health effects of vaping. The researchers studied ...

You can look at some animal cells too. Grab a fresh slide and pop a drop of your food colouring on there. Take your cotton bud and rub the inside of your cheek. Told you you'd need a mouth.