Vitamin concentrates are obtained from marine oils, e.g. cod liver, shark liver, tuna liver, halibut liver, mackerel liver, sole liver, spearfish liver, swordfish liver, herring, sardine, whale liver or seal liver oils, by treating the oil with sufficient alkali to saponify between 10 and 60 per cent of the saponifiable material, separating the unsaponified fraction (semi-concentrate), treating the semi-concentrate at elevated temperature with an aliphatic or heterocyclic polar solvent miscible with the semi-concentrate at such a temperature, and partially immiscible therewith at temperatures below room temperature, cooling the solution to below room temperature, separating the solvent layer, and removing the solvent. Specified solvents are: n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, n-amyl alcohol, iso-amyl alcohol, secondary amyl alcohol, furfuryl alcohol, allyl alcohol, allyl alcohol, diacetone alcohol, b -hydroxy ethyl acetate, methyl formate, ethyl formate, ethyl acetate, methyl acetate, isopropyl acetate, glycol diformate, glycol diacetate, methyl levulinate, ethyl levulinate, methyl aceto-acetate, ethyl aceto-acetate, methyl furvate, vinyl acetate, furfural, propion-aldehyde, croton aldehyde, acetone, methyl ethyl ketone, acetonyl acetone and acetic anhydride.  Advantageously, the rate of saponification is retarded, e.g. by effecting it in the presence of an inert solvent.  Specified inert solvents are: heptane, hexane, petroleum ether, ethylene dichloride, methylene chloride, tri-chloroethylene.  In examples: (1) shark liver oil is treated with sufficient 46 per cent aqueous potash to bring about 50 per cent saponification in the presence of ethylene dichloride, isopropanol and nitrogen gas.  The mass is treated with ethylidene dichloride at 60 DEG  to 70 DEG  C. to extract the unsaponified matter which on treatment with isopropanol containing 1 per cent water and cooling to -18 DEG  C. yields a solution containing more vitamin than would have been obtained by treating the shark liver oil with isopropanol directly; (2) shark liver oil is saponified as in (1) but to effect 60 per cent saponification.  The unsaponified matter is separated from the saponified matter and treated with isopropanol to yield a vitamin concentrate; (3) tuna liver oil is saponified by sufficient potash to bring about 50 per cent saponification and further treated substantially as in the previous example; (4) shark liver oil is saponified by sufficient potash to bring about 50 per cent saponification in the presence of ethylidine dichloride, isopropanol and nitrogen gas; the mass treated with ethylidine dichloride, heated, diluted with water and cooled to about 25 DEG  C. when the solution is separated and the solvent recovered; the vitamin concentrate is treated with isopropanol containing 1 per cent water, and the solution, after heating and cooling to below room temperature yields a filtrate from which a vitamin A concentrate is obtained. This concentrate is treated with ethanol, warmed and cooled to below room temperature yielding a filtrate containing vitamin alcohol and a residue containing vitamin ester.  Specifications 528,994, 549,447, 558,820 and 585,573 are referred to.  The Specification as open to inspection under Sect. 91 includes also the use of alicyclic aldehydes and propylene chlorhydrin as polar solvents; and enzymes to saponify the esters.  This subject-matter does not appear in the Specification as accepted.