I found this question and answer on Yahoo! Answers and thought it was quite interesting so I thought I would share it here. For anyone who is also into medieval history they may find this very interesting. [I also corrected the typos from the original text and added some images I felt were suitable.]
The Question
How were wounds treated during medieval times, especially sword wounds?
The Answer
Depends on the era you are talking about. Early in medieval times and for the poor in later medieval times armor was light or non-existent. As such wounds were often to the head and torso. Limbs were amputated and swords were capable of slashing damage as well as blunt and piercing damage.
Against better armored opponents wounds were typically directed against the legs, face or crushing blows rather than piercing and slashing types of wounds. A common tactic was to bring your weapon in under the shield of an opponent against the lightly or unarmored legs. Once the opponent was down you could then deliver a killing blow.
Until the US Civil war casualties in battle were left where they lay unless they were high ranking or important people until after the battle was finished or unless they were mobile enough to retreat from the battlefield on their own power. Treating the wounded was considered a very minor consideration in a battle and also considered a waste of valuable manpower until the US Civil war when ambulance services first started. You see later in WW I that the same ambulance principles were adopted in Europe then late mostly post WW II in Asia. As such survival rates were low among the wounded until then. Medicine was very primitive early in the medieval times but later in the period surgeons became a common profession and proliferated among the armies.
Foreign matter was a big deal in those times as infections killed the majority of the wounded. Some ancient Celt and Greek units fought naked or mostly naked as it was felt that bits of cloth embedded in a wound were actually more dangerous than the enemies weapons themselves.
Animal urine was a common attempt to reduce infection rates at times and in some places. So too was sealing the wound with a brand thus cauterizing the wound and reducing external chances of infection.
Late in medieval times swords were in disfavor as battlefield weapons. They could not pierce the heavier armor of the day and were ineffective as slashing weapons again due to the better armor. They were favored primarily for symbolic use and against lightly armored opponents like peasants and non-European targets. In Japan and China due to the lack of metal armor Swords remained effective and favored weapons. They could do significant damage to the folded leather armor worn by enemies in the time period.
The weapons favored by soldiers late in medieval times were spears, pole axes, maces, flails, lances and especially the bow and arrow which has repeatedly been show the most lethal weapon on the battlefield all through the medieval times until being replaced by crossbows and firearms.
In the early days mostly there were attempts to staunch the wounds. If the injured took a crushing hit to the skull they might have drilled a hole in the skull to relieve pressure on the brain. Salves of various effectiveness would be applied to fight infections. Pain killers in the form of teas, booze and even opium in some areas would be given to the wounded to ease suffering. Then they waited. If an organ was pierced it was a slow agonizing death usually and invariably fatal. If too much blood was lost it was fatal. Infections were often fatal. Sometimes men would recover mostly from grievous wounds only to die of a hospital infection before they could get out away from the rest of the wounded. Bleeding was used at times and sometimes caused enough damage to kill a man who might otherwise have survived. Experimental medicine was common as most wounded were going to die anyway so any experimental chance was better than none.
Stitches were not common as there was little knowledge of antiseptics or the need for them. As such stitching a wound could in itself be more lethal than the wound was by causing an infection. Some sort of antiseptic had to be applied to even bother with attempts at stitches.
My Thoughts
I found the question and answer because I was looking for medieval treatments for tetanus - a common infection for sword, axe and arrow wounds - basically any kind of puncture wound is susceptible to getting infection. Often people died of tetanus after battles because there wasn't any quality treatments for the condition. The person who wrote the answer doesn't mention tetanus infections specifically, rather he just refers to infections - of which there many different kinds of infections people could die from after a battle.
I also wanted to note that sometimes warriors deliberately dipped arrowheads, swords, axes, etc in excrement in order to dramatically increase the likelihood of infection for their enemies. This was effectively a cheap kind of poison as anyone so wounded would likely die slowly (and very painfully) of infection even if they survived the battle.
