Incapacitated
If an NPC or the MC is reduced to zero or below Health Points in Combat they are Incapacitated (except in the case of NPCs if reduced to -10 or below, if playing Iron Man mode, when they are killed instead, and removed from the game).
An incapacitated MC will recover consciousness after the fight, but will be left with just 2 Health Points and a few Stamina Points, plus a permanent Injury reducing one or more of his Attributes (Strength, Dexterity and/or Beauty).
Incapacitated NPCs must be attended to after the combat, before the MC leaves the battlefield. The MC can tend to them with a Doctor's Kit, which will restore them to a total of 25 Health Points and leave them fit enough to function again - but this requires Medicine skill 40+ to use, will be used up in doing so, and costs $600 to buy. Use of a Doctor's Kit however means that the NPC will not be left with a permanent Injury reducing one or more of their Attributes. If not brought round with a Doctor's Kit, the NPC will suffer permanent losses of a few points off one or more of their Strength, Dexterity and/or Beauty.
Under Grimdark mode, stat losses to the MC and NPCs resulting from Incapacitation Injuries are increased - e.g. from 2 points to 5 points per incapacitating injury. Also, in future releases such wounds may be accompanied by permanent reductions to the respective Attribute caps, to reflect permanent disability - maybe if also playing Ironman mode. Expensive treatments at the Doctor's Hall may be able to rectify disabilities though.
Alternatively anyone can Stabilize incapacitated NPCs without using special medical supplies: this will restore them to a total of 5 Health Points, but will leave them Injured. Once thus Stabilized, NPCs can be further Comforted by the MC before leaving the battlefield, which takes another 6 minutes and will restore another 5 Health points, giving them a total of 10 - fit enough to travel.