Canabis Protectio

I came upon the following mural in my recent trip to Bologna, Italy. I can't comment on the history or the meaning of it but I surely recognize our beloved plant.

Anyone with knowledge in Latin, could you please translate "Canabis Protectio"

Let's protect cannabis? Cannabis protects us?

fucking sick find man!

*sets as BG*

Great find dude!!
As far as I can tell it means "protector" but thats only what I found from a quick google search.
http://www.wordnik.com/words/protectio