Hydroxypropylmethylcellulose is a nonionic cellulose mixed ether, also known as hydroxypropylmethylcellulose, which is used clinically mainly in ophthalmology as a lubricant or an excipient for some drugs. Hydroxypropyl methylcellulose has good stability, the appearance is mainly white powdery or granular substances, most of which can be dissolved in water or the appropriate proportion of ethanol, and its solubility can change with the viscosity. Hydroxypropyl methyl cellulose has a thickening capacity, PH stability, water retention, film-forming properties, enzyme resistance and many other better qualities, so it is widely used in various industries. The main uses of hydroxypropyl methylcellulose in the pharmaceutical industry are the production of coatings, as ophthalmic lubricants, the base of jelly-like topical drugs or thickening agent water retention agent. Among them, ophthalmic drugs are most commonly used because its aqueous osmotic pressure is basically the same as tears, which causes little irritation to the eyes and allows it to come into direct contact with the eyeballs. Many medications may contain hydroxypropyl methylcellulose, which is a stable ingredient that causes little harm, and patients should not be alarmed when using medications that contain this ingredient. If the patient has a previous history of relevant allergies or any discomfort after use, he/she should go to the hospital and consult a doctor to avoid accidents.