While Wikitravel is not a medical encycopedia, the following topical article offers some suggestions for a First aid kit for travellers. You may not be able to purchase, or even require all the items on this list, and in some cases you may need a doctor's prescription to avoid having the items confiscated by border police or customs officers if your bags are inspected. If in doubt, consult a competent medical professional for advice.
Many people have different ideas on what is necessary for them - some people take more stuff, others are better at improvisation.
Regular Medication': If you are taking any form of medication, take it with you along with a copy of the prescription. Make sure it's carried in hand luggage on planes. The prescription will help if you do need to replace it, or customs are unsure about what it is.
Antidiarrhea: Loperamide Hydrochloride (Imodium) is the most common form of anti-diarrheal medicine for over the counter use. NEVER use it if there is blood in the feces - this could be an indication of something much more serious and requires immediate medical attention.
Anti-inflammatory: Ibuprofen (Nurofen) is good both as an anti-inflammatory and also as a general analgesic (pain killer). Other people prefer to use Paracetamol, or an Aspirin Paracetmol combination.
Condoms: AIDS and Hepatitis are much more common in some parts of the world than others, and unprotected sex is highly risky. Even if you're travelling with a partner who uses some other form of protection, it's worth taking them as a precaution as even minor stomach upsets can affect the effectiveness of the contraceptive pill. Having said that, if she's not feeling well, you probably won't need them!
Sunscreen: Make sure you take an appropriate level of protection for your skin and the area you are visiting. An after-sun lotion might help, too.
Feminine protection: worth listing as part of the checklist.
Insect repellent: if you are travelling to an area where biting insects are a problem.
Off the beaten Track
If you are going away from major towns and cities where medical help may not be accessible, you might like to consider taking a fuller first aid kit. Make sure you have the knowledge to use it, too! Consider water purification tables, sterile sets, and so on.
Now that you have your kit assembled, why not go here?