People, brush your teeth before communion. You'll clean the rest of your body and dress up in nice Sunday clothes before Divine Liturgy, so why not clean out your mouth as well? Trust me, the priest does not want to smell your nasty morning breath when you come up to the chalice with your mouth wide open.
All joking aside, we need to really examine the purpose of communion. It is to be united with God through Christ and with our fellow Christians. Piety is a good thing, but when we get so focused on things like whether I should brush my teeth or take my medicine before communion or not, you're replacing the whole nature of communion with "pious practice," and that is not a good thing.