I am a registered First Aider (one of the perks of my government employer) so took some time to learn about First Aid. I'd be interested to see what others think of my kit and what they'd add to it. Clearly some items are peculiar to me (contact lenses and earplugs, for example) whilst others would be essential in any kit. Ultralight is a compromise but how far we compromise in this area is debatable. That said, most items in a medical kit are already small and lightweight, so I don't feel the compromise is so very harsh.
My Kit, in a red Alpkit Apollo stuffsack, and always placed within a drybag containing my other 'keep-dry' essentials, weighs 96g and contains the following:
Painkillers - aspirin, paracetomol and ibruprofen
Savlon antiseptic alcohol wipes
1 set of thin plastic gloves
Steristrips - various sizes
Robust, waterproof plasters
3 sterile dressings (various sizes)
Insect bite cream
Spare shoe lace
Water purification tablets (for emergencies rather than general use)
Swiss Army Knife - “Ranger”
There are various items I do not carry as, in an emergency, other items will fulfil the role - the prime example is a triangular bandage as I can use my MSR Pack Towel to do that. I do not carry a bothy-bag or a survival bag as I have both a shelter and a sleeping bag and mat. I used to carry antiseptic lotion but found alcohol wipes to do a better job outdoors as the skin dries quickly so a dressing can be applied more easily. I don't carry syringes as I do not have the experience to use them, nor is there anything I can inject. I do not carry a snare wire or fishing line, for example, as I might do in the wilderness as it really does not fit my requirements. Finally, my iPhone has John 'Lofty' Wiseman's SAS Survival Guide and the St Johns Ambulance First Aid applications. They are useful additions if you have an iPhone.
It would be intriguing to see what others carry...