I actually bought blue vervain a few months ago. I never tried it because I was doing well with the program I was on (so I thought), and then later read somewhere on this site that the few who were taking it didn't have much success with roundworm, so I just never took it.
I have a whole box full of herbs and supplements that I bought with hope, never took or didn't work. I hope I have finally found the one, and can get rid of all the others. I hope.