Summary Hypertension is a major and growing public health problem. It is responsible for the mortality of millions of people around world, and is increasing each year. Nevertheless, the understanding of the relationship between the composition of the heart's cells, hypertension and health diseases is still very incomplete. The present study focuses on the evaluation of the attributes of some hearts of Spontaneous Hypertension Rats (SHR), comparing with SHR which received additional amounts of polysaccharide (SHR+P) and with wistar rats (normal blood pressure) by Thermal Analysis. Some differences could be seen between groups, as the residue content after 800°C was different for rats from different groups, and of wistar rats hearts samples showed 5.3±0.3& of residues vs. 8.3±1.5& of the SHR. DSC profiles for wistar rats showed one intense endothermic event at 160°C, with enthalpy transition of 450 J g-1 and more three small events. Thermal analyses curves also showed some differences between freezing and no freezing samples, probably associated to the denaturation of proteins and degradation of organic materials.