I have taken it for a year or so. I seems to be effective against bacteria, virus and fungus though not as good for larger parasites, at least not in my case. If you use it for long periods of time or in very large doses, you should probably buy some good bacteria for your intestines like acidophilus and add it to you protocol. I have taken 60 drops one day as a test and could handle it well, but you should start out in small doses cause it's potent.