Lavender is an essential oil containing plant which has been used on by Razi and BuAli in Iranian traditional medicine as sedative and pain killer. In this study pain killer effect of lavender essential oil was evaluated using a pharmacological animal model. Rat (weghit+25-30g) in group of six were subjected to lavender essential oil by aromatherapy (inhalation) using 100, 200, 400 micro liter of oil. A control group and an indometacin (10 mg/kg) group were selected as negative and positive control respectively. Then the rats subjected to acetic acid, then their abdominal twitched were monitored and recorded. Significant differences was observed between control group and the cases with 200 and 400 micro liter lavender essential oil (p=0.001). Based on the results, it seems inhalation of lavender essential oil was reduce the pain, therefore this known Iranian traditional medicine product, namely lavender can be used alone or with other medication for pain treatment