Hello Samida
I have not tried pressing herbs with this oil press, but I don't think it would work. First of all, it says in the instructions that the material to be pressed must be dry, otherwise the machine will clog (and I have already experienced THAT with nuts that are too juicy...), and the pressing screw will be too narrow for the leaves.
If you want to press herbs, leafy vegetables or wheatgrass, for example, I recommend a slow juicer with a vertical auger, such as the one from Omega.
Good luck!