Anaphylactoid reactions in patients receiving intravenously (IV) administered vitamin K have been widely reported. A recent review of the literature along with the US Food and Drug Administration (FDA) adverse drug reaction database uncovered a total of 155 cases, 27 of which were fatal and with the true number no doubt being much higher. The manufacturer has sufficient concern over the safety of IV administration of vitamin K that it was voluntarily removed from the Canadian market. Anaphylactic reactions and fatalities have occurred even when IV vitamin K was given at low doses and by slow dilute infusion. Of the reported 155 cases, 21 cases with four fatalities occurred in patients who received doses smaller than 5 mg of IV vitamin K. Reactions in patients receiving vitamin K by a non-IV route do occur but are much less common.