Abstract: The present invention provides novel compositions comprising a Nigella sativa L. polyunsaturated fatty acid fraction. The present invention also provides novel compositions, particularly topical compositions, comprising octadecadienoic acid and/or octadecenoic acid. The present invention provides novel methods for treating and preventing fungal infections, bacterial infections, skin conditions, anal fissures, hemorrhoids, inflammation, pain, allergic reactions, and septic wounds by administering, preferably topically administering, an effective amount of a composition comprising octadecadienoic acid and/or octadecenoic acid, or a composition comprising the Nigella sativa L. polyunsaturated fatty acid fraction.