I installed Varnish_Cache extention and now all my product links is messed up, html code show on frontend.
I'm on version 1.9.1.
Every product link look like this in the Frontend:
Does anyone have the same problem? How can this be fixed?
Varnish can be quite a beast to get going, there are a few extensions available.
As a first step, I'd check that your varnish cache has been cleared, and that varnish is actually running.
Next would be to check the varnish config; depending on the extenson you can 'hole-punch' sections, or block sections from being cached. This doesn't sound like your issue though.