To evaluate the effects of the use of omega 3 at different doses, following the response through stereological and morphometric evaluations in doxorubicin-induced acute cardiotoxicity in an experimental rabbit model. Thirty healthy adult New Zealand rabbits were divided into six groups with different doses of omega 3 treatment, GT125, GT500 and GT 2000, receiving doses of 125mg / kg, 500mg / kg and 2000mg / kg, respectively. The induction of acute cardiotoxicity with doxorubicin was treated for six days prior to intravenous administration of 10mg / kg single dose. Then, the animals were euthanized and myocardial samples were collected for stereological and morphometric evaluations. The stereological evaluation showed an increase in the transverse area of cardiomocytes between the SHAM and GT2000 groups and an increase in the interstitial collagen volume density between the SHAM and GT500 and SHAM and GT2000 groups. The omega 3 500mg/kg dose has the potential to attenuate the fibrotic effects of doxorubicin use and the use of a single dose of 10mg/kg doxorubicin can be used as an acute dilated cardiomyopathy induction protocol in an experimental model using rabbits.