The inclusion criteria were: Iranian ethnicity, being primiparous, aged between 18–35 years, full-term pregnancy, singleton pregnancy, cephalic presentation of the fetus, having automatic contractions, examining the dilatations (3–4 cm) at the moment of enrolling in the study, suitable pelvis status, having intact amniotic sac, not having consumed painkillers within 8 hours before enrolling in the study, absence of any identified liver, pancreas or respiratory diseases, not suffering from pregnancy and obstetric symptoms (e.g., preeclampsia, chorioamnionitis, placenta abruption, abnormal fetal heart rate at the moment of enrolling in the study), absence of olfactory disorders or sensitivity to herbal medicine according to the participant.