Essential oil is extracts made in oil form from plant with medicinal value and other beneficial properties.
There are many methods of formulating it. Most prevalant methods are distillation and cold pressing.
All these oils have wide benefits and are mostly used for external purposes. For intake kalonji oil or black seed oil and other such are used for overall health benefits.
But widely it is used in panchakarma treatment, massaging, even during swedam treatment to increase the treatment effectiveness.
This treatments are suggested for patients with joint pain, spinal cord issues, respiratory ailments etc. This can be easily absorbed and strengthens the muscles. During sweden treatment it helps in soothing the inflammation and relaxes the wind pipe.