Oxygen heterocycles are one of the most common heterocycles in drugs and natural products. Oxetene has high polarity and is also a good acceptor for hydrogen bond, which contributes to the metabolism and chemical stability of its host molecules. When substituted for commonly used functional groups such as gem dimethyl or carbonyl, oxetane units can induce profound changes in water solubility, lipophilicity, metabolic stability and conformational preference. Four of the FDA-approved drugs contain oxetenes: Orlistat, Paclitaxel, and two of its derivatives, Docetaxel and Cabazitaxel. Currently, oxetane-containing building blocks are flourishing in medicinal chemistry and drug discovery.