A transmitted narrative about Khālid ibn al-Walīd mentions an unusual episode involving a poisonous substance. Its value as a historical report must be assessed separately from the possibility of karāmah in principle.
Whatever its historical standing, the account must not encourage anyone to experiment with poison or endanger themselves. Preservation of life remains the general obligation.
Karāmah is understood as divine grace, not a controllable or safely repeatable human skill.