Under federal law, any product intended for the prevention or treatment of disease is a drug, and it is illegal to market new drugs that do not have FDA approval. In 1989, the FDA’s Health Fraud Branch issued instructions and a sample regulatory letter indicating that it was illegal to market vitamin products intended for treating yeast infections. In 1990, Nature’s Way and its president, Kenneth Murdock, settled an FTC Complaint by signing a consent agreement to stop making unsubstantiated claims that Cantrol is helpful against yeast infections caused by Candida albicans.

Nature’s Way promoted Cantrol with several versions of a self-test—one of which is pictured below—based on common symptoms the manufacturer claimed were associated with yeast problems. The FTC charged that the test was not valid for this purpose. The company also agreed to pay $30,000 to the National Institutes of Health to support research on yeast infections [11].