Homeopathic products are big business, grossing at least $3 billion a year. A 2007 survey estimated that 3.9 million adults and 910,000 children used them. These figures have only increased during the past 10 years.

One uncomfortable fact about homeopathic products, which are substances meant to treat patients by mimicking the symptoms of an illness, is that the Food and Drug Administration (FDA) doesn’t regulate them. This means that:

• Manufacturers are not required to submit a new drug application before selling them.

• Manufacturers are exempt from meeting Good Manufacturing Product (GMP) standards.

• Manufacturers are exempt from finished-product testing for identity and strength.

• And, as an added bonus, homeopathic products are allowed to contain higher amounts of alcohol than other drugs.

Because no one is looking, poorly made and dangerous products slip through. In 2012, for example, 10,000 cases of “poison exposures” were reported; most occurred in children who were less than five years old and some required medical treatment.

For these and other reasons, the FDA held a meeting on April 20 and 21, 2015, to discuss the regulation of homeopathic products. The FDA sought “written comments from all interested parties, including, but not limited to, consumers, patients, caregivers, health care professionals, patient groups, and industry.” With so many competing interests in the room, it shouldn’t be surprising that nothing happened. Nonetheless, about a year and a half after the FDA meeting, on Nov. 15, 2016, the Federal Trade Commission (FTC) took a stand, declaring that homeopathic products cannot include claims of effectiveness without competent and reliable scientific evidence. If no evidence existed (which is always the case), this fact must be clearly stated on the label.

In order to understand homeopathic products and the controversies that surround them, we need to go back to the beginning.

Homeopathy was the creation of Samuel Hahnemann, who practiced in Germany and France between 1779 and 1843. Hahnemann was disturbed by the brutality of 19th-century medicine, which included bloodletting, leeches, emetics, cathartics, and skin blistering with acids. He wanted a safer, better way to treat his patients.

Hahnemann’s epiphany came in 1790. While eating powder from the bark of a cinchona tree, Hahnemann developed a fever. At the time, it was known that cinchona bark, which contained quinine, could treat malaria. Hahnemann believed that because cinchona bark had caused him to have fever, and because fever was a symptom of malaria, medicines should induce the same symptoms as the diseases they were treating. For example, vomiting illnesses should be treated with medicines that cause vomiting. (Homeopathy literally means “similar suffering.”) To be on the safe side, however, Hahnemann also believed that homeopathic medicines should be diluted to the point that they aren’t there anymore. Although the active ingredient was gone, Hahnemann believed that the final preparation would be influenced by the fact that the medicines had once been there. In other words, the water in which the product was diluted would remember. (Given the finite amount of water on earth, it’s comforting to know that it doesn’t actually remember where it’s been.)

To understand how homeopathic products are made, let’s look at one popular product made by Boiron, a French company that describes itself as a “world leader in homeopathic medicines.” The product is called Oscillococcinum.

Boiron makes Oscillococcinum by homogenizing the heart and liver of a Burberry duck, diluting it in water 100-fold, and then repeating the hundred-fold dilution 200 more times. A solution this dilute doesn’t contain a single molecule of the Burberry duck. In fact, the preparation is so dilute that not a single molecule of the duck would be found if the final volume were that of the universe (about 1080 cubic meters). The duck is gone. From a scientist’s standpoint, Oscillococcinum is one gram of sugar. Nonetheless, a pack containing six “doses” of Oscillococcinum costs $8.00. So it’s really expensive sugar.

The label for Oscillococcinum claims that it “reduces the duration and severity of flu symptoms,” including “body aches, headache, fever, chills, and fatigue.” At the end of these claims is a small superscripted asterisk that refers the consumer to an equally small statement on the back of the box: “These ‘Uses’ have not been evaluated by the Food and Drug Administration.”

Promoters of Oscillococcinum argue that the product is of value if only because it’s a lot safer than other remedies out there, many of which are quite harmful. For example, some doctors will prescribe an antibiotic, like the all-too-conveniently-named Z-Pack, which contains azithromycin. Antibiotics can cause allergic responses or select for resistant bacteria. Worse, some parents will use over-the-counter cough-and-cold preparations. In 2007, the FDA issued a warning against these preparations in young children—a warning long overdue. Between 2004 and 2005, the CDC found that more than 1,500 young children had suffered hallucinations, seizures, and heart problems caused by cough-and-cold medicines containing stimulants like pseudoephedrine. Three children died as a result. Further, these products do little to relieve symptoms. Oscillococcinum, on the other hand, doesn’t cause any of these side effects.

When people suffer adverse reactions to homeopathic products, like the poisonings referred to above, it’s because they aren’t really homeopathic. In other words, they might contain an active drug. Because homeopathic products aren’t regulated, consumers are on their own.

The worst aspect of homeopathic products is when people use them to treat conditions that should be treated with real drugs, like antibiotics for bacterial infections or bronchodilators for asthma or steroids for severe eczema. Or, as was the case for a 45-year-old woman named Penelope Dingle in Australia, chemotherapy for a treatable cancer. Dingle paid for her choice with her life.

In a better world, the FDA would regulate homeopathic products. Manufacturers would have to meet labeling and manufacturing standards and products would have to be proven to be safe and effective before they could be sold. If this happened, homeopathic products would disappear from the shelves. Then, patients or parents would have to use their own water or sugar to treat themselves and their children. It would certainly be a lot cheaper and consumers can be reassured that it would be just as effective.

Paul A. Offit, MD, is director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and the author of Do You Believe in Magic? The Sense and Nonsense of Alternative Medicine (HarperCollins, 2013).