When our daughter was ten weeks old, we had to make an ER visit. I didn't know that the more babies cry, the more air they swallow, so the more gas problems they have. She had done a LOT of crying that night (sudden double ear infection) so the ER doc said to give her Mylicon because the main ingredient is simethicone which is not absorbed by the body.
We found gripe water to be useless. I think the things in it work in large enough amounts, for instance I know I get bloat relief if I drink enough fennel tea (though it's nasty), but I don't think a few drops are enough to help anyone.