The results of long-term feeding experiments with three species of animals which received considerable amounts of soyabean oil hydrogenated in different ways confirm the safety-in-use of this type of product. Just like saturated or cis monoenoic fatty acids, monoenoic and polyenoic fatty acids with the trans configuration always have to be supplemented with an adequate amount of cis-cis linoleic acid. The unfavourable effects observed in rabbits after prolonged feeding with one of the studied hydrogenated fats were to be expected in view of the marginal amounts of linoleic acid present in the diet they received. In human nutrition, considering the limited use as such of that particular type of extremely hydrogenated fat with a high melting point, it can be concluded on the basis of present knowledge and with an ample safety margin, that the fats investigated have no unfavourable nutritional effects. With regard to the prevention of cardiovascular disease it is desirable to limit the amount of saturated, as well as trans fatty acids, in order to be able to supply an adequate amount of linoleic acid in the diet.