This works perfectly about 95% of the time. If my son is fussy, gassy, or won’t eat even when he is hungry, I give him this by itself in a bottle and he takes it right away, presumably because he likes the taste. Once in a blue moon, if he is extra fussy, I need to coax him to take it. Once he drinks it, he instantly calms down, as in the very second he drink the last sip, at the latest. It does not knock him out. It is not harmful so I don’t feel guilty using it. It just calms him down so he can resume drinking his formula and then go to sleep.