This is an interesting question because you want to say, "yes, of course." But hold on. This may not be true. When the US was being founded in the 1600's-1700's, they were still burning witches or herbalists/midwives in Europe. Modern Medicine was being born and the new country of The United States of America was too. Herbal Medicine did not get the foot hold within the minds of Americans as it was in Europe and Asia. Immigrants were coming here with this knowledge but medical science was thought of being better than their traditional ways and they forgot or did not rely on the old information.
There are herbalist in this country and some are quite good. For most of us, herbal medicine is folklore or not taken seriously. Marketing companies take advantage of this and spread all kinds of unfounded claims. Those dealing with difficult medical situations can fall prey to these companies. Herbal medicine should be treated as effective as medical medicine. Medical medicine tends to act faster than herbal, but both if used properly can be healing. The key word is used properly. False claims are made for herbal medicine or they use the wrong part of the plant or the wrong solvent is used. There are side effects just like in medical medicine and there can be reactions with other drugs or herbs that can cause adverse effects.
To make it more difficult, herbalists tend to misunderstand essential oils, as it is fat soluble medicine not water or alcohol solvent medicine. A herbalist will think that they know herbal medicine. They will think that rosemary herb is the same as rosemary essential oil. In this case this is pretty much so because it is the essential oil in rosemary that gives it much of it's medicinal properties. Then take St. John's Wort as a herb that is known to treat depression. The essential oil is thought to do the same. This is not true. The essential oil of St. John's Wort has nothing to do with the treatment of depression but if you check the internet, you will find that it does. Buying a capsule of dried St. John Wort leaves will not help depression, as the medicine is only found in the flower and it is fat soluble. Being careful of info on the internet is always important. There is a misunderstanding within the herbal community that the herbal solution will be the same for the essential oil. Essential oils often have very different actions compared to the herbal standards. Looking into a herbal book will not help you understand the essential oil unless the herbal medicine is based on the essential oils within that plant.
Herbalists also look down upon essential oil production as part of big commerce and waste. Essential oils can be used as money within the global system. They are a commodity like corn and wheat and traded as such, but herbals are not. In the production of essential oils, a large amount of plant material is consumed to produce a small amount of oil. 3% yield is considered excellent. The rest of the plant material is cast away. As a herbalist you can see how they deplore this waste and are not inclined to use essential oils because of this.
Within the European culture, alchemists studied essential oils because they saw the world as corrupt and soiled. In the act of wanting to turn iron into gold, they were attempting to purify or bring back humanity to a more spiritual, blissful place. When distilling a plant, they brought in the gross plant material and passed steam through it. A vapor was realized with the steam and disappeared only to reappear as an essential oil. This process was thought to be one that could refine or redeem humanity. Actually the name essential within essential oil refers to this pursuit. Alchemists in their study of essential oils were looking for the fifth element or quintessential element. Essential oils are not essential to the life of the plant as many plants produce none or little essential oils. Of course they do play a role in many plants. Take knock out roses that have become so popular. They have no scent; produce no essential oils. They may be pretty to look at, but are worthless as an essential oil product. Any plant with scent has healing properties. Knock out roses have lost their healing properties.
The trick to finding the healing properties is to first know where the medicinal properties are. Is the medicine in the root, resin, leaves, needles, flowers, fruit, bark or wood. A plant can produce many medicines or just one. It is important to know where the medicine is.
The next thing that you need to know is how soluble is the medicine. Is it water soluble, alcohol soluble, acid soluble, or oil soluble? A plant can produce many medicines and have many soluble properties. Take Lion's Tail for example. As a tea, water soluble, it produces a euphoric medicine that counters depression and helps you feel happy. As a fat soluble medicine it produces a maceration that helps women or repressed people find their voice without being hateful or angry. The oil helps you assert yourself without being violent or aggressive. If you had assumed that the maceration or essential oil of lion's tail was the same as the water based medicine, you would be very wrong.
Yes, essential oils are part of herbal medicine, but often misunderstood and miss used. Only through proper education can we correct these misunderstandings. So do not accept that an herbal definition will be correct for an essential oil. Rely more on the chemistry of the essential oil to define the use of the oil. Yes, the herbal definition and essential oil definition can be the same, but often not .
Then their is the spiritual history of essential oils that needs to be respected. They often bring with them personal definitions that will help people heal mentally. emotionally, and spiritually. We are not just bodies. We are much more than that and essential oil treatments are very helpful in recovering from trauma, abuse, long term illness, emotional wounds of all sorts, and just making our way in the world as spiritual beings with questions and wonderments.
Plant medicine is medicine of the planet. Much of the pills we take now were studied first as plant medicine then developed into pills to help with different ailments. It is often thought that the cure for a disease is within some plant that has yet been discovered or studied. There is still so much to learn about the science of essential oils. Rose is probably the most enigmatic oil in that many of its chemical components have yet to be defined or discovered. They can see that a chemical is there. They just do not what it is. It is undefined.
We will keep our minds open and continue to study. There is much to learn and much to understand when working with oils and herbal medicine.