don't share your personal hygiene with your friends

an email from my mom:

For your own health, do not share your personal hygiene with your friends, even your boy friends. Personal hygiene includes tooth brush, tooth paste, chap sticks, lipsticks, etc. Remember to wash your hands all the times, especially before meals. Even dad and I never share each other’s tooth brush. Bacteria and virus can spread very quickly through your own saliva or any kind of body fluid.