There are different things you can use to heal your character when they are injured. Some can be used together to stop bleeding and heal faster. Others do not stack together. Gauze is not the greatest for healing up but good to use to stop bleeding. You start off with a stack of 5 when your a fresh spawn, you can not craft gauze. You can craft bandages with 2 scraps of cloth, you can evolve those into dressed bandages with honey in a bottle. You can craft First aid kits with bandages and saline (water + salt)
Gauze heals 11% Health and stops light bleed Bandage heals 11% Health and stops light bleed Dressed Bandage heals 20% Health and stops light bleed First Aid Kit heals 60% Health and stops light bleed
You will need to reapply depending on severity of bleed.
Pills and Etc...
There are quite a few different types of pills and other miscellaneous health related things (like loaded syringes) none of them have any effect on your health or life unless you have the H1Z1 Virus then some of them help to stave off the virus. If you are infected with the virus you can not cure yourself of it. The only way to get rid of the virus is to die.