Source Core Rulebook An injury
is activated by applying it to a weapon or ammunition, and it affects the target of the first Strike made using the poisoned item. If that Strike is a success and deals piercing or slashing damage, the target must attempt a saving throw against the poison. On a failed Strike, the target is unaffected, but the poison remains on the weapon and you can try again. On a critical failure, or if the Strike fails to deal slashing or piercing damage for some other reason, the poison is spent but the target is unaffected.