A basic first aid kit should be part of every traveller’s packing list but what you need to carry depends on your destination and health. Every first aid kit should contain the following items:
Aspirin or ibuprofen
Antiseptic cream
Band-aids (variety of sizes)
Blister kit (moleskin or duct tape are popular choices)
Insect repellent
Sunscreen
Add Dramamine if you suffer from motion sickness.
List of medical contacts and translations for common aliments and medications.
This should be sufficient for most travellers needs but add any non-prescription medications that you use on a regular basis. Always carry your prescription medications in their original container with a copy of your prescription to ensure you do not run afoul of the local constabulary.
Check the US State Department and Australian Smart Traveller websites for additional health information for your destination and enhance your basic first aid kit as required to meet any unique requirements. For example, malaria prevention medication is recommended for many countries.