Background and aims: Diabetes mellitus (DM) is a multifactorial metabolic disorder characterized by hyperglycaemia caused by insulin deficiency or insulin resistance. It is a global public health problem. This study aimed to determine specific pharmacological effect of quercetin in water soluble and liposomal preparations in experimental diabetes mellitus. Material and methods: We examined the effect of Corvitin and Lipoflavone (at the dose of 10 mg / kg body weight) in a comparative study in white rats with type 1 diabetes and type 2 diabetes coupled with obesity. To simulate the forms of diabetes mellitus most analogous to those in humans we used Streptozotocin at the doses of 30 mg / kg and 50 mg / kg. We tested the levels of glucose, glycosylated hemoglobin, C-reactive protein, and interleukins 6 and 4 in the blood. Results: In animals with type 1 and type 2 diabetes Lipoflavone significantly reduces glucose and glycosylated hemoglobin levels compared to the rats treated with Corvitin. When administered to animals with diabetes, the effect of quercetin in liposomal form on the concentrations of IL-6, IL-4 and Creactive protein is also larger compared to the water-soluble form. Conclusions: Water soluble quercetin preparation Corvitin and to a larger extent liposomal preparation of this flavonoid, Lipoflavone, show anti-inflammatory effect and restore key parameters of carbohydrate metabolism in experimental type 1 diabetes mellitus and type 2 diabetes coupled with obesity, reducing blood glucose and glycosylated hemoglobin levels.