evidence: What is a Zapper? Research Scientist and Author, Dr. Hulda Clark invented a simple positive offset square wave frequency generator powered by a 9-volt battery and called it a Zapper. She wrote many books about zapping parasites which she believed was beneficial to boosting the immune system. Zapping is considered experimental, which means that the science has not been evaluated by the FDA. Read the latest books by Hulda Clark to learn about the many ways Dr. Clark experimented with a Zapper. [...] What about parasites, viruses, & bacteria? Will this help with...? There are a lot of politics and laws about what a merchant can state when selling experimental devices such as a Hulda Clark Zapper. Let us try to explain. Because Dr. Clark does not manufacture Zappers or nutritional supplements, she can state whatever she believes in the books she publishes. It is considered free speech. Although her research and experiments have benefitted hundreds of people over the years, the Hulda Clark Zapper has not been evaluated by the US FDA. Without a double-blind study approved by the FDA, any claims that the Hulda Clark Zapper kills parasites, viruses, and bacteria are considered unsubstantiated.