Introduction: Rosemary essential oil can be used for treating dyspepsia, mild spasmodic disorders of thegastrointestinal tract, externally as analgetic in muscular and articular pain and minor peripheral circulatory disorders.It is important to explore its analgesic potential and its influence on the pharmacodynamic and pharmacokineticproperties of paracetamol. Methodology: Rosemary essential oil was applied to mice orally (doses: 10 and 20 mg/kgb.w.) for pharmacodynamic tests for seven days. Rats treated with rosemary essential oil for seven days orally (5 and10 mg/kg b.w.) were used for the examination of the influence of essential oil on the pharmacokinetic properties ofparacetamol (applied on the 7th day p.o. or i.v.). Pharmacokinetic parameters were analyzed in blood samples obtainedfrom rats’ tail veins, with the HPLC method. Results: The essential oil of rosemary shows analgetic properties. Therosemary essential oil increases pharmacological effects of paracetamol and does not change paracetamolbioavailability. Conclusion: The herbal drugs could change the pharmacodynamic and the pharmacokinetic propertiesof classical drugs and they could also change the safety of classical drugs use in human population.
