Objective To study the antioxidant properties of Capparis spinosa (C. spinosa) honey and propolis and the effect of combined honey and propolis administration on urine volume and electrolytes in rats. Methods C. spinosa honey [1 000 mg/kg body weight (b.wt)], propolis (100 mg/kg b.wt), honey/propolis mixture (C. spinosa honey 1 000 mg/kg b.wt/ propolis extract 100 mg/kg b.wt), distilled water (1 mL/kg b.wt) and furosemide (10 mg/kg b.wt) were orally administered to five groups of rats for 21 d. Urine volume, blood and urine sodium, potassium and chloride were measured. The antioxidant activity of propolis and honey was assessed and their total phenols and flavonoids were determined. Results Propolis and C. spinosa honey contain polyphenols including flavonoids and propolis demonstrated higher antioxidant activities than honey. Honey significantly increased urine volume and urine electrolyte excretion. Propolis had no significant effect on urine volume, but co-administration of propolis and honey caused significant diuresis. No major changes were observed in plasma electrolytes with the use of honey, propolis or their combination. Conclusions Honey and propolis have antioxidant activity and contain polyphenols including flavonoids that are more pronounced in propolis. Honey has a significant diuretic activity alone or in combination with propolis. This is the first study comparing the diuretic effect of co-administration of propolis and C. spinosa honey with furosemide.