Biometric authentication improves security by using unique biological traits, such as fingerprints, facial recognition, or iris patterns, to verify an individual's identity. This method is highly effective as biometric data is difficult to replicate or forge, providing a higher level of assurance than traditional password-based systems. By implementing biometric authentication, organizations can enhance access control, reduce fraud, and ensure that only authorized users can access sensitive information or secure areas, thus bolstering overall security.