Fragrance oils are composed of many aromatic ingredients. Many of the common ingredients used in fragrance oils include: carrier base, alcohols, aldehydes, esters, and other synthetic compounds. These ingredients can be derived from nature or created by scientific methods. Natural ingredients include essential oils, resins, and absolutes. Ingredients that are man-made, commonly referred to as synthetic chemicals, are also found in nature and can be reproduced synthetically using scientific techniques. The synthetic versions are generally less expensive, more consistent in odor and color, and widely available.