Oleic acid is a monounsaturated fatty acid and natural constituent of a number of foods, particularly vegetable oils. On the basis of proven beneficial health effects it is also a possible ingredient in processed functional foods. However, due to its high energy content it is not recommended to increase the consumption of any particular fat, but to substitute other lipids with oleic acid. While there is a well-established consensus that replacing saturated fats in the diet with oleic acid or other unsaturated fats contributes to the maintenance of normal blood cholesterol levels, a series of other effects has also been studied, including the modulation of inflammatory markers, blood pressure, insulin sensitivity, gastrointestinal functions and even various cancers. This book discusses oleic acid’s health effects, as well as its production, and how it is used.