The "Zapper" device was introduced by Dr. Hulda Clark who has stated in her book "Cure for All Diseases" that it can help provide relief from many illnesses caused by parasites such as giardia, cryptosporidium, flukes, other colon parasites and intestinal parasites in humans and in other animals. This in turn, she claimed, could help the body's immune system fight cancer and other serious diseases. She later added more information in "The Cure for All Cancer".
The zapper is not a scam and not a faith based instrument. It is easily demonstrated that at the very minimum, a good zapper, such as ParaZapper™ CC2, using Low Voltage Pulsed Electric Fields ( LVPEF ), will directly kill microbes such as bacteria, protozoa, fungi, and other microbial organisms that may be parasitic or pathogenic in nature, possibly even the virus. It is also believed but not proven, that zappers can not only kill microbes but, through the use of vibratory stimulation, may also help boost the immune system.
There has only been one study done on this topic but it did show that the majority of users experienced noticeable results from using the zapper.