Another "sword" movie

[s_taillebois]

They really wouldn't have needed the poison as such. Any of these weapons which were used, might have been wiped down and possibly treated with a light oil or other surface protectent. So, wounds caused by period weapons no doubt would have been infected with all manner of residual bacteria from the last event or person's blood.
Of course the period people would have been unaware of this factor, at least from a causual point of view.
Poison, they did use it on projectile weapons. In Europe there were continued attempts to do so, well into the firearms era. Although I'm not sure how any compound applied to, and fired out with a musket ball could have been effective.
Have to remember however, in warfare in Europe- they did have a long tradition of using biological and chemical elements to their tactics. That's how the bubonic plague got into Italy, it was the result of a siege tactic which had unintended consequences on the besiegers.

[SzabolcsWaldmann]

I heard poisoning was not so common, not even for assasination efforts. Firstly, It would come off quite quick. a few chops and a rain and off the poison is washed <img src="/forum/images/icons/wink.gif" alt="" /> The wielding of such a weapon would be any way you look at it dangerous for the user as well. Besides, Swords are meant to kill in battle, not afterwards <img src="/forum/images/icons/wink.gif" alt="" />
Poisoning a blade was not chivalric, I guess, but it did not make so much sense either. And I know there are lots of dangerous poisons, acting instantly, but most aren't THAT quick, are they?

Szab

[s_taillebois]

That and with the periods battlefield medicine, cauterizing wounds was not uncommon. So in general such tactics would have been ineffective. The battlefield medicine of the time (and the unwashed hands, unsterile equipment etc) probably did a fine job of finishing many off...who needed long acting poisons?
Stylets however, it would seem more likely that such could transmit a poison. But given the standard of medical care regarding stab wounds, why bother?
Plus, certain military technologies do tend to be modified by social pressures. For the cavalier class, certain things were fine to do to the lower orders, but some social pressure modified these when applied like to like.
That said, the Chinese did develop very early forms of airborn chemical weapons,(such as burning sulpher) but these were more of an irritant agent (and to compromise vision) than a lethality.