Abstract A collaborative study was conducted to compare the NF XII method and a GLC method for quantitatively determining menadione in pharmaceutical products. Ten collaborating laboratories analyzed 6 Pharmaceuticals encompassing tablets, capsules, and a liquid. Menadione is extracted with diethyl ether from ground tablets; slip capsules are opened and the contents are emptied into the ether along with the capsule parts. After filtration and removal of the ether, the residue is redissolved in n-hexane. The menadione sodium bisulfite injectable is transferred to a separatory funnel and extracted with chloroform and sodium hydroxide, evaporated to dryness, and redissolved in n-hexane. Menadione is chromatographed on a 6’ × 3mm id glass column packed with 1% neopentyl glycol succinate on 100–120 mesh Gas Chrom Q and operated at 135°C. The carrier gas flow is adjusted so that menadione appears within 5.5–6.5 mhi. Because of the coefficients of variation, additional study is recommended.