Pharmacognosy is the study of pharmaceutical ingredients or raw medicines derived from natural sources such as plants, microbes and animals. This involves study of the environmental, mechanical, biochemical and physical properties. The human body is believed to find plant-derived pharmaceutical products easier to adopt due to the fact that they occur in nature and are not synthetic. In research, the natural substance may be inactive in its normal physical state, such that it can require a chemical reaction or alteration to transform it into its active form. The active ingredient is often derived directly from the plant, but on other occasions the active ingredient may be generated by synthesis whilst producing a compound which is identical to the plant extract.