Immune functions are indispensable in defending the body against pathogens and thus play a vital role in maintaining health. Immune functions are disturbed by malnutrition, aging, physical and mental stress or unwanted lifestyle. Therefore, the intake of immunomodulatory dietary supplements is considered effective in improving immune functions and reducing the incidence of immunological disorders. The main focus of this study was to evaluate the antioxidative status of lyophilized plant extracts, such as rosehip (Rosa canina), sea buckthorn (Hippophae rhamnoides), echinacea (Echinacea angustifolia) and bilberries (Vaccinium myrtillus), their cytotoxicity and nutritional status, in order to effectively utilize them as ingredients in a dietary supplement with immunomodulatory properties.