The article on antithrombotic therapy1 that appeared in the January 23, 1995, issue of the Archives was introduced as a synopsis of the proposed guidelines for an American College of Chest Physicians Consensus Conference on Antithrombotic Therapy, including recent updates and information that will likely influence future recommendations. The authors recommend reversing the anticoagulant effects of warfarin when the international normalized ratio is between 6.0 and 10.0 and "the patient is not bleeding," with vitamin K given by slow intravenous injection in a dose of 0.5 to 1.0 mg, and when the international normalized ratio is between 10.0 and 20.0 and "the patient is not bleeding," with a higher dose of vitamin K (3 to 5 mg), also by slow intravenous injection. Their statement that "intravenous vitamin K therapy has been associated with a slightly increased risk of anaphylaxis" is specious at best and deadly at worst. Well over