I always recommend that you carry the best first aid you can get. I myself only carry minimal medical equipment for short weekend treks, but for longer treks I take modern first aid supplies.
My medical kit with bandages, an eye wash glass bottle, botlle of salt, bottle of iodine, scissors, tweezers, and some herbs wrapped in paper.
An 18th century bottle.
Another 18th century bottle close to the one I use. They do come in a variety of shapes and sizes.
Three 17th century medical bottles.
Three modern bottles gleaned from the local hospital. Certainly representative enough to pass as period.
18th century surgical kit.
18th century medicine chest.
Close up of the chest above.
The cloth bags I use for straining water when trekking and I need to top up my canteen. If it is raining, I catch water in my kettle, but if not raining then I must collect water from available water holes.
The larger one strains the larger debris and slime from the water first. I simply scoop the water out with the bag and let the water run through the bag and into my kettle. If it is clean enough, then I boil the water and it is ready for use. If not clean enough, then I strain it again through the double bag or one bag inside the other that you see here.