If you drink green beer be careful. The green dye used in that St. Patty's Day pint may turn your teeth green. The green dye that is added to beers will temporarily stain your teeth green (the same way red wine stains your teeth red). If you aren’t careful, the next day, your teeth may still be green! According to dentists, the key to avoiding this problem is to brush your teeth immediately after drinking the green stuff. Don't fall asleep, or, more accurately, pass out without brushing. Who is actually going to brush their teeth at the bar? Nobody! So just remember to do it when you get home.