That depends which one it is and which browser(s) it affects.
Which browsers are you using, and what are the symptoms - where are you being redirected, and when and how often does it happen?
Please be more specific. Typically, web browser redirects are caused by rootkits/trojans or malicious web browser extensions. You may use Malwarebytes or any other malware removal tool to remove possible malware. In case, it's a malcious or PUP extension, you will have to uninstall it manually. For some users, a tool called AdwCleaner works well too.