This product contains Diphenhydramine, and doesn't include any dosage information for children under 6, so use with that in mind. As with all medications, you should probably consult a doctor before using at all with your children, and take care not to give them too much.
My daughter likes the grape flavor, so that's the one we get. She calls it "purple tea". We get the 4 fl. oz. bottle, which comes with a dosing cup.
The product does seem to get the job done. It induces drowsiness, the plus side of which is that my kids will settle down so that they don't make their colds or flus worse. And, of course, the real purpose, they seem to feel better after they've taken it, and they cough and sneeze less.
I don't use it often though, even when they're sick. Because I'm frankly paranoid about them getting too much, and I am not a fan of Diphenhydramine.