WASHINGTON — Homeopathy has long been a magnet for controversy, earning a devoted following among patients who insist its remedies are safe and effective, while attracting criticism from many doctors and researchers who say its treatments offer no more help than a placebo.

After problems within the industry in recent years, the Food and Drug Administration says it wants to revisit how it oversees homeopathic products, which can be manufactured and marketed without prior approval from regulators.

Should the FDA regulate homeopathic remedies such as Cold-Eeze the same way it does over-the-counter drugs such as Advil? Should it hold products such as Zicam, which contains small amounts of zinc, to the same safety and efficacy standards that it requires for Tylenol?

Hundreds of public comments have poured into the FDA ahead of two days of hearings that begin Monday. The agency said it wants more data to “better assess the risks and benefits” of homeopathic remedies, which have become a mainstay on modern pharmacy shelves, often sold alongside over-the-counter pharmaceutical drugs.

The FDA has not made any decisions about whether to change how it approaches homeopathic products, said Cynthia Schnedar, director of the Office of Compliance at the FDA’s Center for Drug Evaluation and Research.

The FDA has issued nearly 40 warning letters since 2009 to companies making homeopathic products, Schnedar said.Last month, the agency warned consumers not to rely on over-the-counter asthma products labeled as homeopathic, saying they have not been evaluated for safety and effectiveness.

In 2009, the FDA warned consumers to stop using several types of Zicam cold remedies after reports of more than 130 cases of people losing their sense of smell; the company issued a recall.

The following year, Hyland’s Teething Tablets were recalled after reports of reactions in some children; the tablets later were reintroduced with a new formulation.

Homeopathic medicines have had the same legal status as regular pharmaceuticals since 1938, when then-New York Sen. Royal Copeland, who was a trained homeopath, helped shepherd a landmark food and drug law through Congress.

In the 1970s, lawmakers directed the FDA to review the safety and effectiveness of over-the-counter medications. But the agency deferred reviewing homeopathic treatments at the time and last evaluated its policies in 1988. It has allowed most prescription and nonprescription homeopathic products to go to market without prior approval.

Homeopathic remedies, derived from plants, minerals and other substances, often are tailored to individual patients.

The FDA’s decision to revisit the issue has worried advocates of homeopathy, who fear that any broad new regulations might unfairly cripple the industry.

“Obviously, people are alarmed and wondering what the FDA is up to,” said Jennifer Jacobs, who practiced homeopathy for 30 years and is now a clinical assistant professor of epidemiology at the University of Washington School of Public Health. “It seems to me that they have bigger fish to fry.”