evidence: The synthetic vitamin K3 is very toxic, and as a result, has been banned from over-the-counter sales in the United States because ingestion could result in allergic reactions, hemolytic anemia, and cytotoxicity in liver cells.[2] Vitamin K use requires caution in neonates, patients with hereditary hypoprothrombinemia, renal impairment, cases of over anticoagulation due to heparins, and hypersensitivity to vitamin K. [...] Vitamin K toxicity is extremely rare. The only reported toxicity comes from menadione, which has no use in humans. Its toxicity is thought to be associated with its water-soluble properties. When toxicity does occur, it manifests with signs of jaundice, hyperbilirubinemia, hemolytic anemia, and kernicterus in infants.