Essential oils are liquid extracts of various potentially beneficial plants. They can be obtained from leaves, flowers, seeds, fruits, roots, bark, resin, wood and other parts of plants. Manufacturing processes can extract these compounds from these plants. Common extraction include Steam distillation, infusion, supercritical CO2 extraction and solvent extraction. Essential oils are widely used in the areas of chemical industry, pharmaceutical, industry cosmetic industry, and food industry. Essential oils often have a much stronger smell than the plants they come from and contain higher levels of active ingredients. This has to do with the amount of plant matter required to make essential oil.