Aromatherapy is the use of essential oils to support & promote physical, emotional, and/or mental health. Much like herbalism, aromatherapy may be used by the layperson for routine or minor concerns, but it’s best to consult a trained aromatherapist for more serious conditions (or where an underlying condition is present). Professional aromatherapists have been trained to understand the chemical constituents of the various oils, and to know what contraindications are likely to be present.
This is a field that is heavily dominated by the untrained, and a good deal of inaccurate information is circulating, so please be careful about where your information comes from. Even health professionals commonly spread misinformation, when they are not knowledgeable about essential oils, specifically.
One final note: ALL the professional aromatherapy organizations specifically oppose the Raindrop Technique (TM), which is demonstrably dangerous. If your practitioner (or information source) recommends this technique, I’d encourage you to look elsewhere.