i'd probably refuse to do so for role playing reasons of course ;) but i just wondered

i could cheat the item and check i suppose but that seems like a very slippery slope

With the innate Assassin ability Poison (next attack causes poison), you can indeed inflict poison with Tasherons Bow.
(they count as Poisoned Arrows IIRC).

Not sure if HLA: Assassinate works with the bow (every attack counts as a backstab, i dont think it does)