Alzheimer's disease (AD) is a progressive degenerative disease of the central nervous system (CNS) that mainly affects people over 65 years of age, resulting in loss of memory and cognitive functions such as language, attention, orientation and reasoning. According to the World Health Organization (WHO), 24.3 million people worldwide suffered from AD and other types of dementia in 2007, with a doubling of this number every 20 years. That Organization also stresses that the impact of AD in developing countries will be even greater because of the increase in life expectancy. There is no known cure for AD; the treatments currently used are intended to alleviate the symptoms and progression of the disease. Factors that trigger the disease are not yet well understood, but there is evidence of a reduction in the activity of phospholipase A2 (PLA2), a key enzyme involved in the inflammatory response in the hippocampus of patients with AD. Conjugated linoleic acids (CLA) are isomers of linoleic acid (C18: 2 n-6) which are present mainly in ruminant products, with milk fat being the main source of CLA in the human diet. In vitro and animal studies have shown that CLA cis-9, trans-11, the major isomer of CLA in milk fat, has beneficial properties to human health, whose mechanism of action seems to involve, at least in part, modulation of the inflammatory response. In particular, some studies have shown that CLA cis-9, trans-11 modulates the activity of the PLA2 enzyme in several tissues, and that this isomer of CLA is actively incorporated into rat brain tissue. Based on the above information, a study was carried out with the objective of producing a butter naturally rich in CLA cis-9 trans-11 by means of the inclusion of sunflower oil in the diet of dairy cows, and to evaluate the effects of the ingestion of this butter on the memory and on the activity and expression of PLA2 in rat hippocampus. The results of this study showed that the consumption of the CLA-rich butter, as compared to a control butter, increased the activity of the main subgroups of PLA2 (i.e. cPLA2, sPLA2 and iPLA2) in the hippocampus of the animals, this increase being closely correlated with an improvement in the memory of the animals, suggesting that intake of CLA-rich dairy products plays an important role in the prevention or treatment of AD, which needs to be proven in future studies with humans.