The zapper has no side effects other than maybe it might injure your good bacteria, which you can easily take a probiotic for. And the herbs without the zapper are basically useless, as I found when I continued to take the herb part of Dr. Clark's protocol, but stopped zapping, and everything PLUS 'cancer' came back (except the hiatal hernia, thak goodness).
But if you believe taking a level of poisons aka 'drugs' high enough to kill parasites all over your body, think about it for even a minute. How can that be good for your body??? Especially as easily as we can get reinfected. You're going to be a lifer (of a very shortened life, most likely) on some kind of horrid poison. Whee. Sounds healthy to me.