Experiments were carried out in the genetically hypertensive obese rats of Koletsky type (SHR/N-cp obese), in their lean siblings (SHR/N-cp lean) and in the rats of Han-Wistar strain. The effect of long lasting terguride treatment was monitored when the animal represents a control for itself. Blood was sampled to heparinized capillaries from retrobulbar plexus in the same animal before and after the terguride treatment. Long lasting terguride treatment shows decrease in "area under the glucose tolerance curve" in all groups of animals, increase in glycaemia in normotensive males, increase in insulinemia in normotensive rats of both sexes and in SHR/N-cp lean males and decrease of insulinemia in SHR/N-cp obese males, increase of triglyceridemia in normotensive rats of both sexes and in SHR/N-cp lean males, and decrease of triglyceridemia in SHR/N-cp lean females and SHR/N-cp obese of both sexes, increase in cholesterolemia in normotensive and SHR/N-cp lean males, decrease in cholesterolemia in normotensive, SHR/N-cp lean and obese females. Thus ambivalent effect of terguride treatment is more expressive in glucose tolerance and in plasma triglycerides. Ambivalent effect of long lasting terguride treatment is profoundly expressed in correlation between pre-treatment state of individual parameters and the effect of treatment expressed in percentage changes in post-treatment state. In all cases statistically significant correlation coefficients show negative mark. Thus it is apparent that terguride increases monitored parameter when this parameter is low before treatment, and vice versa. When it is considered "area under the glucose tolerance curve", significance was attained in all groups, when judging basal glycaemia, significance was attained in normotensive and SHR/N-cp lean rats of both sexes, taking into account insulinemia, significance was attained in normotensive and SHR/N-cp obese rats of both sexes, when analysing plasma triglycerides, significance was attained in normotensive rats of both sexes and in SHR/n-cp lean females and obese males, when we consider total plasma cholesterol, significance was attained in normotensive rats of both sexes and in SHR/N-cp lean males. From the clinical point of view it must be underlined that terguride is potent to increase insulinemia. Thus there is open a possibility of the other clinical indication of the mentioned drug.