I have heard people put hot sauce or something that tastes awful on their fingertips so when they bite their nails, they will get a nasty taste in their mouth and won't bite them or not. Some people put tape on their fingertips to prevent them from biting them. I don't know if these work, its just what I heard. The way I stoppped biting my nails was a little harsh: everytime I caught myself biting my nails, I would slap myself in the face. Not too hard. It helped because whenever I went to bite my nails, I remembered the slap. The whole point of the slap is that it helps you remember not to bite your nails.