I suppose this is a no-brainer, but mini containers of drugstore medicine are one of my travel essentials. I like to keep things in their original containers because drug laws vary so much from country to country, and I’d rather not be caught with some unlabelled pills in a pill case. There’s a bunch of info about bringing medicines back into Canada here, but this part is relevant: The drug must be in hospital or pharmacy-dispensed packaging, the original retail packaging, or have the original label attached to it clearly indicating what the health product is and what it contains.
So I really like things that come in small containers or are individually packaged (like the Lactaid, above). A lot of drugs that come in boxes with blister packs are labelled on the blister pack, so remove the box and they’re pretty easy to pack. Avoid bottles unless they’re tiny — they’re bulky and take up a lot of space in your bag. You can often find travel-sized medicine in the travel section at the drugstore (for whatever reason, I find WAY more travel-sized medicine in US drugstores), or pick some up when you’re at the airport. At most airports, you can find a large selection of various drugstore medicines in single or small dose packages that are perfect for packing.
Always check what’s allowed and not allowed into a country before you leave — seemingly innocuous stuff can be illegal in some countries. For example, Sudafed cold medication, or anything containing pseudoephedrine, is prohibited in Japan.
My travel medicine kit includes the following:
All of this fits into a small LeSportsac pouch so it’s easy to pack! The key is to just take a little bit of each medicine — you can find most of these almost anywhere, so you just need enough painkiller or cold medication (or whatever) to get you to a drugstore so you can buy some more.