How do you get a child to stop sucking their thumb?

well when my daughter was 3 i treid to get her to stop. i bought this stuff called STOP its a nail polish that is clear with cayanne pepper in it. unfortunatly my daughter liked the spicy and she is almost 8 and still sucks her thumb when she is tired. good lick.

Don't call attention to the thumb sucking. The more you call attention to it, the more the child will do it.

I offered my kids a reward for every night they put a band-aid on their thumb/fingers (I have 2 of them). If they fell asleep with the bandage on, the next night they got the reward (which gave them incentive to do it again that night). It has worked for my 7 year old thumb sucker (I should say former thumb sucker). My 4 year old still puts her fingers in her mouth all the time (and her teeth are showing the damage). I won't push it with her until she starts losing her teeth, and then I will push harder the and she still does it. It took my son less than 3 weeks, so maybe it is just the ages.