Hydroxypropyl methylcellulose (HPMC) is a semi-synthetic polymer derived from cellulose, widely used in various industries, including pharmaceuticals, food products, cosmetics, and construction. As a versatile compound, HPMC serves multiple functions, such as a thickening agent, emulsifier, and film-forming agent. Despite its many benefits, like any other substance, it can have side effects. This article aims to discuss the side effects of HPMC, particularly in its pharmaceutical applications.