Drools is a business rule management system (BRMS) and decision management platform that allows users to define and automate complex business rules and decisions in a declarative manner. It is an open-source tool that provides a rule engine to execute rules and enable fast and easy business decision-making processes. Drools can be used in various domains such as finance, healthcare, telecom, and more to manage and automate business rules through its intuitive user interface and easy-to-use rule management features.