I first read about Blue Vervain in The Back to Eden Book. This book is fantastic and has remedies from the 1800s. I read that when all other parasite herbals fail, then use vervain. We shall see. I havent used it long enough to see any results yet, just started. I'm not sure the proper dosage (drops) to take. So im starting off with 20 drops. I cant find the info on how much extract to take. I know you can drink it as a tea, but it takes awful in my opinion. I will get back to you on how to make your own extracts. I just have to find the directions. Until then, check out the website above.