The invention relates to a process for decreasing the amount of cholesterol in a mixture comprising a marine oil, the marine oil containing the cholesterol, which process comprises the steps of adding a volatile working fluid to the mixture, where the volatile working fluid comprises at least one of a fatty acid ester, a fatty acid amide and a hydrocarbon, and subjecting the mixture with the added volatile working fluid to at least one stripping processing step, in which an amount of cholesterol present in the marine oil in free form is separated from the mixture together with the volatile working fluid. The present invention also relates to a volatile cholesterol decreasing working fluid and a health supplement and a pharmaceutical, based on a marine oil, prepared according to the process mentioned above.