Aromatherapy. Dried lavender (Lavendula sp.) and its essential oil in an oil burner. A bunch of lavender is in the background. The candle heats the oil, which is usually mixed with water and a neutral carrier oil, releasing the fragrant volatile compounds it contains. Aromatherapy is a system of alternative medicine which applies essential oils through inhalation and massage. Aromatherapists claim to be able to treat a wide range of conditions. Although the evidence presented is largely anecdotal, some trials have found that it is effective in treating depression, stress and chronic pain. Lavender is used by aromatherapists to treat many conditions.