The invention comprises the addition product of a cobalamin with a hydroxynaphthoic, methylene - bis - hydroxybenzoic, or methylene - bis-hydroxynaphthoic acid which may be nuclearly substituted by lower alkyl of 1 or 2 carbon atoms, phenyl, halo or nitro and a process for separating cobalamin from an aqueous liquid containing the same by adding to such a liquid at a pH of about 4.0 to 10.0 hydroxynaphthoic, methylene - bis - hydroxybenzoic or methylene - bis - hydroxynaphthoic acids which may be substituted by lower alkyl at 1 or 2 carbon atoms, phenyl, halo or nitro, and then acidifying said liquid to a pH of about 1.0 to 4.0 by addition of a mineral acid thereto to precipitate from said liquid an addition product of said cobalamins with said compound. Acidification is effected with a mineral acid, hydrochloric being preferred.; Excess hydroxybenzoic or hydroxynaphthoic acid may be dissolved and removed by acetone or other suitable solvent. Subsequently the cobalamin is extracted from the precipitate with benzyl alcohol, phenols, cresols and chlorinated phenols. Examples illustrate the formation of the addition compound with methylene disalicylic acid, 5-bromosalicylic acid, 5-chlorosalicylic acid, 5-nitrosalicylic acid, 3 - hydroxy - 2 - naphthoic acid, methylene - bis - 3 - hydroxy - 2 - naphthoic acid, 1 - hydroxy - 2 - naphthoic acid, methylene - bis - 1 - hydroxy - 2 - naphthoic acid, 3-phenyl salicylic acid, methylene bis-4-hydroxy benzoic acid, methylene-bis-3-hydroxybenzoic acid, 5-phenyl salicylic acid, orthocresotinic acid and methylene-bis-ortho-cresotinic acid.