Zapper, what's that?
Zapper is a simple square signal generator that is plugged to the human body. It's believed that this can kill parasites, and that parasites (and pollutions) are the source of many or even all of the illness.
I think, that this can work, maybe that's my imagination or autosuggestion, but I feel better, I have more energy and I'm more optimistic.
Is it safe?
IMHO if somebody doesn't have problems with hearth and isn't pregnant, it should be safe, but that's just my opinion. Use at your own risk.
I use it daily, in one, 30 minute session. After each 3-4 days I made one day of a break. After a month, I made 2-3 months of break. AFAIK such schedule is quite popular and was described in many sites. More information about how to use it can be found here. I put the electrodes to my feet but some people prefer to put electrodes on the hands.
Almost all Zippers are build from NE555, unfortunately I didn't have it, so 4093 (2-input Schmitt NAND gates) was used instead. The electrodes are made from aluminium foil.
R1=1M, R2=100k, R3=1k, R4=47k, C1=1n, U1=4093More useful circuits and other ideas how to use this tool can be found here.