Essential oils have been used traditionally for their sedative and antispasmodic effects, thoroughly described throughout aromatherapy literature. Scientific data from animal tests appear interesting but are unsatisfying. On the one hand, they have confirmed many of aromatherapy’s most deeply held concepts; on the other hand, a direct translation to human use is problematic.
Interestingly, clinical results in clear support of essential oils, though rare, were in fact established already in the 1970s. At that time it was possible to convincingly demonstrate the effectiveness of, again, the main components of Klosterfrau Melissengeist for imbalances of the autonomic nervous system in a double-blind study. Over 80 percent of the patients reported good to very good results in the therapy of nervousness, anxiety, depression, inner tension, headaches, dizziness, heaviness in the legs, general exhaustion, fatigue, insomnia, and loss of appetite.
These results have been supported by further studies on the individual components of essential oils. The sesquiterpene caryophyllene proved to be the most effective of all the substances tested. IS Investigating the main components of melissa oil, the alcohols citronellol and geraniol, as well as the aldehydes citronellal and citral showed that citronellal had the strongest sedative effects. Citral was nearly as effective, while geraniol and citronellol were, as expected, practically without effect. The study found that nearly all of the terpenes and phenylpropane derivatives tested possessed very good sedative qualities when administered orally.
The study also concluded that no direct correlation between the type of chemical compound (such as alcohols, ketones, etc.) and efficacy of the substances tested can be observed.
Most of the oil components tested had their strongest effects with the lowest of the tested doses, which was 1 milligram per kilogram of body weight. For a body weight of 70 kilograms this would correspond to a dosage of 70 milligrams, or two to five drops. For the most part, raising the dosage resulted in a reduction of effectiveness, which is also confirmed by experiences in aromatherapy.
If, twenty years after these studies, one were to correlate the components and the oils in which they are predominately found, it would become obvious that experiences in practical aromatherapy are in accordance with the scientific data. The citronellal of melissa and Eucalyptus citriodora and the linalol found in lavender are among the components with the strongest sedative effects. Also, limonene of lemon has a significant calming effect. Oils derived from melissa, Eucalyptus citriodora, lemon verbena, citronella, and other oils with a high aldehyde content also have a strong sedative effect.
Tarragon and basil oil are distinguished by their special effects on the autonomic nervous system and the digestive tract. The phenylpropane ethers, especially estragole (methyl chavicol), stabilize an overactive sympathetic nervous system (sympatholytic effect) and restore a healthy balance between the sympathetic and the parasympathetic nervous systems. The antispasmodic effect of these oils is-as evidenced by their culinary usage-especially pronounced in the digestive organs. The traditional use of Pemod, Ouzo, and other anise-flavored liqueurs after a heavy meal is a familiar example of these effects.
As for their effects on the central nervous system and stress-related symptoms, oils with a high ester content, such as clary sage and Roman chamomile, are equally effective antispasmodics. They reduce tension in stressful situations or with premenstrual discomfort.