It happens all of the time. I don't believe there is any problem whatsoever in doing that. Just make sure your ads relate to your site!

Google does allow you to use Clickbank & Adsense on the same page, but you need to be sure they do not look similar. Google's concern is for their advertisers here. They don't want a visitor to your site clicking a Google ad because they thought it was a Clickbank ad, for example. So they ask that you make the non-Google ads different colors and/or clearly marked so as to differentiate them from Adsense ads.

Here's the link to Google's explanation: https://www.google.com/adsense/suppo...n&answer=32849

John