The minimum would be a few plasters, some painkillers and a sterilizing wipe or two. In some areas you'd carry a snake bite kit, insect repellent or suncream. This can be expanded to include antibiotics, dihorea tablets, butterfly sutures, anti-histamine etc. What's carried depends a lot on the individual, their skill and the area traveled in. A compass needs to be accessible for easy reference, not hidden in a tin.
Soap is of course a very good antiseptic.
I usually carry a pen as a matter of course. A few pieces of paper have numerous uses. As well as leaving messages you can draw maps or diagrams when there is a language barrier. In addition to the tatty piece of string that hides in my pocket I'd take a longer hank when straying from town and probably a few yards of paracord. In certain areas a light rope would be in order.