I know this is late but wanted to add that i used the bitter nail polish and it worked for my 3 year old. I put it on while he was asleep and he never put his fingers in his mouth again after he got that awful taste. However, it was taking away his soothing technique so we had a 2 week battle about going to bed after that. He didnt know how to soothe himself to sleep so it was very very hard for a couple weeks, but its better now and he doesnt put dirty fingers in his mouth anymore. He was getting sick all the time and now he doesnt. I got the polish at amazon.com.