Lavender essential oil (1–5%) decreased the number of marbles buried compared with the control and amyl acetate groups. In the elevated plus maze, 5% lavender essential oil inhalation increased the percentage of time spent on and number of entries into the open arms compared with controls. No effect was seen in the number of closed arm entries or number of beam interruptions in the automated activity chamber. Pretreatment with the GABAA receptor antagonist picrotoxin (0.5 mg/kg) did not modify the behavioral effect of 5% lavender essential oil in the marble-burying test. Lavender essential oil also did not alter [3H]flunitrazepam binding to the benzodiazepine site on the GABAA receptor. Pretreatment with the serotonin 5-HT1A receptor antagonist WAY100635 (3 mg/kg) blocked the anxiolytic-like effect of lavender essential oil and the 5-HT1A receptor agonist 8-OH-DPAT (3 mg/kg). A combination of ineffective doses of 8-OH-DPAT (0.5 mg/kg) and lavender essential oil (0.1%) reduced the number of marbles buried. Finally, 5% lavender essential oil attenuated the serotonin syndrome induced by 40 mg/kg fluoxetine plus 80 mg/kg 5-hydroxytryptophan.