Leave the arrow in for the same reason as a bullet.
With poisoned arrows, it would probably depend upon how fast the pison enters the circulation.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman
Would the bit of the arrow sticking out be cut off? And in the situation of a poisoned arrrow, could it be removed if it hits a non lethal place in the body?
Regular arrows are normally barbed at the back and pulling them out causes more damage. In this case, you surgically remove them back at camp.
If the arrow has penetrated far enough, and/or it's unobstructed, you could snap off the feathery part and push the arrow through the rest of the flesh to get it out. This hurts like hell, but you could do it on the field and still walk around and fight people if you can tough out the pain.
edited 7th Aug '12 2:11:43 PM by SalFishFin
Night Clerk of the Apacalypse.
General first aid is to leave the arrow in. Moving it can cause additional injury and pain. You can carefully wrap a bandage around the shaft near the wound and carefully tie it down to minimize movement of the shaft. When you move the wounded person you have to be careful ot not jostle the arrow or patient too much.
We have a page on it that covers wounds Archery
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edited 7th Aug '12 5:14:42 PM by TuefelHundenIV
Who watches the watchmen?
What is the best treatment to an arrow injury. Would it be best to not remove the arrow? What if the arrow had been poisoned? I've tried researching this online, but haven't found anything. Keep in mind this takes place in a high fantasy, medival setting.