Medicine heals you, but only if you take it — and we all forget sometimes. If you have trouble remembering if you took your medicine (or gave it to a child or pet), mark the schedule right on the bottle.
If the meds you're taking are pills, you can flip the bottle as a reminder or just use a pill box. That's not as easy with liquid meds (after all, you don't want them to spill).
Write out the schedule on the bottle and just check the box after you give or take the medicine. If you don't have enough room on the bottle, no problem. Put the bottle in a clear ziplock and mark that bag.