Essential oils come from various plants and are found in their flowers, leaves, seeds, fruit peels, roots, resins, barks or wood. The plants attract insects or fend off pests. In this way, the lavender oil is obtained from the lavender flower, while the lemon oil is obtained from the peel of the citrus fruit. Depending on the part of the plant, the oils can differ greatly (e.g. cinnamon bark oil versus cinnamon leaf oil). The essential oils are then obtained from these parts of the plant by various processes (distillation, extraction, pressing). It is important for the safe and successful application of essential oils that only pure, high quality is used.