A new chemical named parrodienes has been extracted from parrots' plumage. From the chemical point of view, parrodienes are polyunsaturated aldehydes similar to carotenoids. On the basis of this similarity we organized some biological experiments to evaluate the inhibition of lipoperoxidation of cell membranes induced by CCl4, protection against ultraviolet rays, anti-inflammatory activity and protection from an increase of ornithine-decarboxylase as marker of tumoral skin alteration. The results of these experiments showed that unsaturated dienes (parrodienes) play an important role on the inhibition and prevention of many biological processes that are at the basis of different pathological disorders.