We understand that when showing ads on your site, there may be a few you'd like to prevent from appearing. There are a number of ad control and filtering tools in your AdSense account, which we've listed below to help you determine which ones are right for you.

• Competitive Ad Filter You can enter the specific URL of an ad into the Competitive Ad Filter to prevent ads from that site from appearing on your pages. If you'd like to block ads coming from an entire domain, enter a top-level domain such as www.example.com to block all ads that link to subdirectories below that domain.
  
  
• Ad Review Center The Ad Review Center, located under the AdSense Setup tab in your account, lets you review and filter any placement targeted ads that are appearing on your pages. You can filter ads by type (text or image), or by individual ad groups and advertisers.
  
  
• Category Filtering To use the category filtering feature, you first have to enable the Ad Review Center. Category filtering allows you to block ads from up to 8 categories such as dating, politics, and weight loss, from displaying on your pages. Ads in these categories will be filtered if they're in English, French, German, or Spanish, regardless of how they've been targeted to your pages.

If you still see filtered ads are appearing on your site after you've used these features, please take note of the following:

• Ad filters should become effective within 30 minutes, but in rare cases might take up to 48 hours to be effective. Review the information in our Help Center for more information.
  
• If you use both AdSense for content and AdSense for search, and wish to filter an ad from appearing in both products, make sure that you've entered the correct URL in question in both filters.
  
• If you display ads from more than one AdSense account on one page, you need to filter the URL(s) in both accounts.

That brings us to the end of our troubleshooting series for AdSense for content. Stay tuned next week for tips on troubleshooting issues with AdSense for search.

Posted by Ulrike Jung - Inside AdSense Team