If you throw up less than 2 hours after you take your pill, it is considered a missed dose. But, the next step depends on which pill you threw up. “Missing a pill” when taking combination pills means missing the normal time you take it by 5 hours or more, so you still have time to take another pill. If you miss two combination pills, then you should use back-up protection, like a condom, for seven days. Progestin-only pills (POP) contain no estrogen and a lower amount of progestin, so even missing one pill means you should use back-up protection for at least two days.