Wal Mart has a product in the HBA section, near files, nails, polish etc. It has a white and black lable - and I think that the name is "Bite Stop" or "Stop Bite" or No Bite" somthing like that. My daughter and husband were both nail biters and it was driving me crazy. I bought it for my daughter and they both used it with success. The directions say to apply it a couple of times a day, and with our busy schedule, most days it was only applied once. I tried it on my pinky just to see, and from personal experience, I can tell you that it leaves behind a TERRIBLE taste, days later, even after multiple hand washings! (I'm a compulsive hand washer) It is less than $2 and was better and easier than nag nag nagging! Also - I told my daughter that if we had a microscope and could take a sample from under her nails and look at it under the scope, that the germs would look like a million little worms, so every time that she puts her fingers in her mouth, she is eating worms! I don't know which technique made her stop - maybe the combination, but she is always showing me how good her nails look now and I almost never have to tell her to get her fingers out of her mouth anymore. Good luck! :)