These are all the items you can use to treat yourself for low health, bleeding and infection.
Health Regnerates very slowly over time (if you are not bleeding), the rate is approximately one third of your health bar every hour and this does not happen while you are offline.
To speed up health regeneration, you can use Adrenaline and Morphine injectors.
In order to revive a player, an Adrenaline injector must be used on them. A different inject animation will play so you know you're not injecting yourself.