They don't call it "The Plug" for nothing. From Ashley:
My two month old has bad gas and we have been giving her gas drops, but as soon as we put them in her mouth she spits them out. So I've learned to keep a pacifier on hand while I do it. I put the drops in her mouth and immediately pop the pacifier in her mouth long enough for her to swallow the medicine. She really isn't crazy about the pacifier, but will keep it in her mouth long enough to swallow.
Related: Bottle nipple as medicine dispenser