Although anaphylaxis induced by vitamin K1 seldom happens, 4 allergic cases were observed in the patients we treated recently who were given intramuscular injection of vitamin K1 before renal biopsy. To provide the best clinical evidence, we searched MEDLINE （-May 2005） and evaluated the studies. The studies were only case reports and retrospective reviews which showed the anaphylaxis were mainly allergic dermatitis with different manifestation and reaction time. The serious reactions such as allergic shock was very rare. We conclude that although vitamin K1 anaphylaxis is rare, strict indications should be followed and the drug surveillance on adverse events should be strengthened.