However, toxicity can be caused by menadione, sometimes called vitamin K3, which is a synthetic, water-soluble vitamin K …

When consumed orally, the natural fat-soluble vitamins K1 and K2 do not cause hypervitaminosis K symptoms — they are not toxic, even in large amounts. Because of its toxicity, menadione is no longer used for … Vitamin K toxicity is typically seen in formula-fed infants or those receiving synthetic vitamin K-3 (menadione) injections. Higher dietary intake of vitamin K2 has been linked with a reduced risk of heart disease, risk factors for heart disease, and death due to heart disease in older men and women.