Canola oil (CO) given as a dietary fat deteriorates hypertension-related condition and shortens the life of stroke-prone spontaneously hypertensive rats (SHRSP). Although substances other than fatty acids have been presumed as causatives, CO mimics consisting of oils other than CO also shorten the life. In this study we intended to examine whether or not fatty acid composition unique to CO participates in the adverse effect. CO or an interesterified CO mimic (ICOM) consisting of safflower oil, flaxseed oil and erucic acid was fed as a dietary fat for 13 weeks to Wistar Kyoto (WKY) rats, and clinical and pathological signs were compared. WKY rats were used to avoid the difficulty in evaluating the results in SHRSP due to irregular deterioration in conditions by stroke. Compared to a standard diet, both diets containing CO or ICOM similarly elevated blood pressure, increased plasma lipids, activated hepatic glucose-6-phosphate dehydrogenase, decreased platelets, shortened blood coagulation times and induced abnormalities in the kidney. Thus, CO-specific fatty acid composition appeared to affect the pathophysiology of the rat and produce consequent aggravation of pathological status, especially in SHRSP. However, the existence of causative factors other than fatty acids was suggested by increased neutrophil count exclusively induced by CO. (C) 2008 Elsevier Ltd. All rights reserved.