1) Pepto-Bismol. This pink stomach medicine can sometimes have a strange side effect of turning both your tongue and the surface of your teeth black. The weird reaction comes from a chemical compound that changes color if exposed directly to the tongue, instead of with water. If this happens to you, don’t panic! It can be avoided or fixed by simply brushing your teeth or, for serious incidents, getting a cleaning from your dentist.
2) Over-whitening. Some scientists are still debating this phenomenon, but many feel that the harsh chemicals can thin out your enamel and cause your teeth to become more porous, which actually makes them look dingier. Even if this claim turns out to be false, no one likes glow-in-the-dark teeth, so practice moderation.
3) Cranberry Juice. This and other dark-colored juices contain a lot of pigment which can stain and yellow teeth. They also have a lot of sugar to sweeten its naturally bitter taste, and that is never good for teeth. Try drinking out of a straw, following it up with water, or switching to white cranberry juice.
4) White Wine. Although everyone knows that red wine can stain your teeth, new studies show that white wine can actually do more damage. The chemicals can strip away your enamel and darken your teeth, especially if followed by other staining things like coffee or tea. Avoid brushing your damaged teeth for 20-30 minutes after drinking wine; just swish with water.
5) Sports Drinks. What may seem like a healthy alternative to soda or energy drinks could really contain an acidic pH level that leads to tooth erosion. They also, like many other drinks, have unhealthy amounts of sugar. The best thing to do is drink it relatively quickly instead of slowly sipping it and exposing your teeth even longer to the chemicals.