evidence: Vitamin K1 (phylloquinone) is not toxic when consumed orally, even in large amounts. However, menadione (a synthetic, water-soluble vitamin K precursor) can cause toxicity (infants have developed hemolytic anemia, hyperbilirubinemia, jaundice, and kernicterus) and should not be used to treat vitamin K deficiency. [...] Vitamin K toxicity is rare but is most common in formula-fed infants. The effects of vitamin K toxicity can include hemolytic anemia and jaundice. Jaundice in newborns can cause kernicterus. Treatment is to stop vitamin K and provide supportive care.