Essential oils are made in two main ways: steam distillation & cold pressed. In the former the raw plant material is placed into a vat (similar to a pressure cooker), then filled with highly pressurized steam. The steam collects the oil molecules which when cooled, separate from the water. In the latter, commonly used for citrus oils, machinery is used to press the oil out of the plant. Millions of people around the world have discovered the benefits of pure essential oils. Not all oils are created equally, always look for unadulterated oils from a company with public test results.