Fig. 4.

Effect of essential oil of Eucalyptus (EOE) on writhing induced by acetic acid. Acetic acid-induced writhing test was used to determine whether EOE has an effect on visceral pain caused by an irritant injection. Control (0.9% saline, i.p.), vehicle (almond oil, i.p.), essential oil (11.5, 22.5, and 45 mg/kg, i.p.), or indomethacin (10 mg/kg, i.p.) were injected 30 min prior to administration of a 0.5% acetic acid solution (10 ml/kg). Five minutes after acetic acid injection, the total number of writhing movements were recorded for 30 min. Writhing decreased from indomethacin and EOE (22.5, 45 mg/kg). Each value represents the mean and standard error of mean. *P < 0.05, **P < 0.001 compared to the vehicle group. ^#P < 0.05 compared to the control group. One-way analysis of variance followed by Tuckey’s post hoc test was used. There were 10 mice in the control group and 8 in the other groups. i.p.: intraperitoneal.