Several years ago, while chatting with my sister on the phone, I learned that she didn't have a first-aid kit at home. I was shocked. Even though I don't have one myself, I strongly believe that everybody *else* should have one, just so they don't call me at 3 am for advice on what to do with a bleeding finger.
Here's a list of what I keep in the ol' casa, even if it's not all in the same place:
The Ideal First-Aid Kit
1. Band-Aids of various sizes, including a box of those hideously-expensive clear ones that you can leave on through a shower or two. I don't use any sort of Band-Aid very often, but the minute I run out you can guarantee that I'll slice a finger wide open somehow.
2. An elastic bandage, two inches across. You only need one. If you sprain an ankle falling over the cat, it's nice not to have to hop down three flights of stairs, hop into the car, and try to drive a standard transmission vehicle to the store to pick up something with which to wrap said ankle.
3. A bag of frozen peas or corn, for ice-packing.
4. Gatorade powder, Dramamine or Bonine, and maybe some Pedialyte frozen popsicles. Nothing's better to combat a case of the stomach flu or a really toxic hangover than Bonine/Dramamine and Gatorade or Pedialye. Mix the Gatorade half-strength; drink the Pedialyte or eat the pops straight. This will help you not get too dehydrated when you're garking up every meal you've eaten in the last two weeks.
You might notice that there's no Immodium or similar anti-diarrheal there. That's because, if I have the runs, I'm not going anywhere anyhow. Besides that, if there's something irritating your intestines to the point that your body's trying to expel it, you really *need* to get rid of it, not let whatever-it-is sit around in your gut doing more damage.
5. Aspirin. I don't take Tylenol or acetaminophen-containing things because I challenge my liver quite enough as it is, thank you. If you have more than two drinks a week, you probably shouldn't take acetaminophen, either. It's tough on your liver, and you need your liver.
6. Sharp-pointed tweezers, a pair of bandage scissors, and strong medical tape. You can fix almost any problem with those things.
7. A hot-water bottle. Champion for cramps and muscle strains.
8. Hydrogen peroxide and alcohol, bought in bitty bottles and replaced every few months (the peroxide, that is; the alcohol will keep forever). Buy 70% rubbing alcohol--stronger is not better when it comes to topically-applied alcohol. In a pinch, you can use at least forty-proof liquor for disinfecting cuts, though I'd personally stay away from rum or anything flavored.
9. Double- or triple-antibiotic ointment. Yes, you really ought to have some of this lying around, just in case.
10. A bottle of el-cheapo saline solution, the sort used for contact lenses. I'm not talking about the protein-removing no-rub solution, but the plain old 0.9% saline. It's handy-dandy for washing out cuts or open blisters. Back when I had dogs who were clumsy and/or enthusiastic about running into sharp things, I went through a big bottle every month. It's only 99 cents at the drugstore, if you get the store brand, and when you have a cut that has ook embedded in it, nothing's better for getting the ook out.
There you go. Aside from the Gatorade, hot water bottle, and frozen peas, you can stick all of this stuff on one shelf in your bathroom or kitchen and be prepared in case you end up as ungraceful as I am.