Input sanitization is the process of cleaning and validating user input before it is processed by a system. This practice helps prevent malicious data from causing harm, such as SQL injection attacks, where an attacker can manipulate a database by inserting harmful code. By ensuring that only safe and expected data is accepted, systems can maintain their integrity and security. Effective input sanitization involves checking data for type, length, format, and content. For example, a web form that collects email addresses should verify that the input matches the standard email format. This reduces the risk of errors and vulnerabilities, making applications safer for users.