When a trademark becomes very popular and well-known, it risks becoming "genericized" where it is no longer recognized as a brand but rather as a common term to refer to a class of products. Some examples of trademarks that became generic include Escalator, Aspirin, and Heroin. Trademark owners must aggressively protect their marks through legal action against any infringing uses to avoid losing their intellectual property rights if the mark becomes genericized. Google has so far avoided this fate, while companies like Xerox have faced challenges preventing the generic use of their trademarks despite campaigns. Maintaining a trademark requires continuous legal policing to ensure it remains a protected brand and does not slip into generic status.