In cholestatic diseases, the absorption of fat-soluble compounds, including vitamin K1(20), is low and periodic administration of vitamin K1(20) is often necessary. Due to the low absorption of vitamin K1(20) from the Konakion formulation, late hemorrhagic disease of the newborn also occurs especially after oral vitamin K1(20) prophylaxis with Konakion. We investigated the pharmacokinetics and the safety of a new formulation of vitamin K1(20) in a mixed micelles (MM) solution. Compared to the old formulation (Konakion) using Cremophor EL as a solubilizer, the higher vitamin K1(20) levels (as measured by HPLC) in serum obtained after oral administration of the MM formulation clearly demonstrate a superiority of this new formulation. Additionally, the elimination of Cremophor EL as well as of propylene glycol from the formulation avoids possible adverse effects associated with intravenous or intramuscular administration. Furthermore, in most cases, the discomfort of parenteral injections can be overcome by simple oral administration even in children with severe cholestasis.