What is the best way to get a three year old boy to stop sucking his thumb?

Advice from the parents of the Answers.com Q&A community:

Normal Development and 'Readiness'

He will stop when he is ready. Help him learn to calm down when he is nervous or unhappy and eventually he won't need his thumb. Keep him active and using his hands, you can play Baseball, fingerpaint, bake cookies or anything else really fun while sucking your thumb. Turn off the tv and send him outside. If he still sucks his thumb when tired or sleeping that will eventually stop.

Binky's or Pacifiers

Do you give them a binky to suck on instead? That might help.

My sister's children, ages 3.5 and 5, still use their binkys. She has tried to take them away, but the kids just start sucking their thumbs, instead. The pediatrician recommended that she poke pin holes in each binky, so the kids lose suction when they use them. This way, supposedly, they will lose interest in sucking altogether when they are not getting the expected reward/sensation. The idea is that they feel they are still in control, but don't get as much pleasure out of it and will eventually stop.

Using a binky is okay when the child is still young, but be careful if the kids are older because it can cause dental problems. We've taken to encouraging the older young child to use their blankets instead to comfort themselves when tired or upset, since these can be taken away and don't cause dental problems!

Adversive edible liquid or pastes

You can apply some edible liquid that is bitter in taste, to his thumb. You can also use the cruse extract of Aolevera plant.but please see to it that it should be edible material -- do not use anything else.

Rizwan.

If you find something non toxic that tastes bad and let it dry on their fingers, they will keep it out of their mouth. Vinegar is good or a mild pepper sauce or such. They do make a non-toxic substance called "bitter Apple" that you can rub onto his thumb while he sleeps. (or to keep your cat from chewing through wires!) Ask around your neighborhood and local stores to see where it is carried.

My 4 year old daughter still sucks her thumb & if I was to put anything on her thumb she'll just wash it off while I'm not looking.

I sucked my thumb until i was 10 and every time my mom put any nasty taste on my thumb i washed it off or sucked it off.

Avoid products with alcohol !

Most mouthwashes contain some alcohol. These should not be used with children.

Ways to stop Thumb Sucking:

Try A Reward System

'Reminder Liquid' Idea

Do Not Try Negative Reinforcement

Weaken the Habit by engaging him in different play activities