The authors report the process and results of an evaluation of a midwifery aromatherapy service for mothers in labour: This study of 8058 mothers in childbirth, is the largest research initiative in the use of aromatherapy within a health-care setting. The study involved a wide range of participants, from mothers who experienced a low risk, spontaneous labour and birth, to those whose labour was induced, and those who had vaginal operative delivery and Caesarean section. The study-took place over a period of 8 years, which enabled a more challenging test of the effect of aromatherapy on intrapartum midwifery practice and outcomes. In the study a total of 10 essential oils were used, plus a carrier oil, which were administered to the participants via skin absorption and inhalation. The study found little direct evidence that the practice of aromatherapy per se reduces the need for pain relief during labour, or the incidence of operative delivery. But a key finding of this study suggests that two essential oils, clary sage and chamomile are effective in alleviating pain. The evidence from this study suggests that aromatherapy can be effective in reducing maternal anxiety, fear and/or pain during labour. The use of aromatherapy appeared to facilitate a further reduction in the use of systemic opioids in the study centre, from 6% in 1990 to 0.4% in 1997 (per woman). Aromatherapy is an inexpensive care option. In 1997 when 1592 mothers used aromatherapy, the total cost was 769.17 Pounds. The study reports a minimal incidence of associated symptoms. Out of 8058 mothers, 1% (100) recorded an associated symptom. These were mild in nature. The successful model of integrated practice that this aromatherapy study presents, offers a useful example for other units to consider.