Research background. The use of plants and their extracts in treatments of chronic diseases is widely known in traditional medicine. The aim of this study is to determine the effects of 10-day consumption of Prunus spinosa L. flower extract on blood glucose, glycaemic load, serum α-amlyase and serum insulin, in normoglycaemic and hypergycaemic (alloxan) mice model. Experimental approach. Normoglycemic and hyperglycemic (alloxan treated, 150 mg/kg body mass) C57BL/6 mice were treated daily, during 10 days, with Prunus spinosa L. flower extract by gavage. The sugar content within extract was determined by HPLC analysis. In mice, blood and serum blood glucose level and OGTT-test were determined by blood glucometer. Serum insulin was determined by ELISA assay and α-amlyase by colourimetric assay. Results and conclusions. The Prunus spinosa L. flower extract increased glucose in normoglycaemic mice by 30 % after 1st and 5th day and by 17 % after 10th day of consumption in normoglycaemic mice. It is a consequence of released sugars because sugar analysis revealed 59.8 mg/L monosaccharides, mainly fructose (55.7 mg/L) and glucose (24.3 mg/L) within the extract. On the opposite, the extract consumption, reduced serum blood glucose in alloxan-induced hyperglycaemic mice by 29 % after 10 days of treatment. Oral glucose tolerance test also confirmed that that in the hyperglycaemic group treated with Prunus spinosa L. flower extract glucose homeostasis was improved and showed decrease in blood glucose, since the blood glucose over the period of 120 min, glucose homeostasis is faster achieved after treatment with shows that in Prunus spinosa L. flower extract. Serum insulin increased by 49 % and serum alpha amylase by 46 % after 10 days of treatment with Prunus spinosa L. flower extract in hyperglycaemic group. Thus, it can be concluded that Prunus spinosa L. flower extract improved glucose tolerance, enhanced insulin secretion and lowered serum α-amylase activity. Novelty and scientific contribution. The results examined for the first time the potential of Prunus spinosa L. flower extract in hyperglycaemia management.