Mavala Stop. It's from Sweden and it's wonderful! You put in on like nail polish every few days. The bitter taste is a quick reminder to break the habit. We started it a few days ago and already the results are totally and completely AMAZING! We spent all day yesterday running errands and she didn't suck her thumb once! That never happens. She is so proud of her progress and I never would have dreamed that the change would occur so quickly!