You can prevent your ad from running next to certain types of content on placements by choosing the Exclude categories option below the Edit placements section of your ad set. There are five categories.

All five categories can be excluded on Audience Network and Instant Articles, but you can only block the categories Mature, Tragedy and conflict and Debatable social issues on in-stream video. Learn how to exclude categories in Ads Manager.

The five categories you can exclude are:

• Debatable social issues: Topics related to debated social issues, such as religion, politics, immigration and more. Does not apply to Audience Network mobile apps.
• Mature: Topics including violence, firearms, sexual content, profane language and more. Does not apply to Audience Network mobile apps.
• Tragedy and conflict: Topics that contain emotional or physical suffering, such as crime, illness, bullying and more. Does not apply to Audience Network mobile apps.
• Dating: Websites and apps that have been categorised as dating. Ads may still appear alongside content about relationships and dating.
• Gambling: Websites and apps that have been categorised as gambling, where winners receive money or prizes. Ads may still appear on websites or apps where people play games just for fun.

* Nguồn: Facebook