The majority of essential oils produced in the world market are used in the food flavor and fragrance industry, so essential oils are often found on the market adulterated with similar essential oils, chemicals and synthetics, as well as extenders such as dipropylene glycol. Unfortunately, even the type used in food can be adjusted with chemicals from a natural source and still legally be called natural. Therefore, it is wise to purchase only from a reputable aromatherapy source. Essential oils work in harmony with the body to normalize and balance. They produce certain effects that we can count on, but can also adapt to the needs of different people.
Oils can directly or indirectly affect the body's physiological systems.
For instance, a couple of drops of peppermint taken orally can aid digestion and inhalations of mucolytic oils can relieve respiratory symptoms. Used topically for their antiseptic and soothing effects, essential oils can successfully treat minor skin conditions. It has been demonstrated that the application of certain essential oils to the skin can produce vaso-dilation which in turn causes warming of underlying muscles, however this is an indirect effect of the oil acting on the superficial tissues, it is not a pharmacological effect produced as a result of the oil entering the systemic circulation via the skin. In addition, because of the effect of relaxation on the brain and the subsequent sedating or stimulating of the nervous system, essential oils can also indirectly raise and lower blood pressure and possibly aid in normalization of hormonal secretion. Because of olfaction's direct connection to the brain, sending electrical messages directly into the limbic system, essential oils can have effects on emotions and mental states.