he Food and Drug Administration's drug labeling and marketing regulations play a critical role in protecting the public from dishonestly advertised and unsafe drugs. Partly as a result of recent court rulings, the agency is now re-evaluating these consumer protections. It must be careful not to water down its rules in a way that would endanger public health.

The drug industry has long been unhappy with the F.D.A.'s regulations on marketing its products, and lately industry advocates have been taking their complaints to court. They claim that many rules barring companies from making questionable claims about drugs, or even advertising some products, violate drug makers' First Amendment rights to free speech. Their arguments are receiving an increasingly warm reception as the federal judiciary becomes more conservative.

Earlier this year drug makers won a major victory when a sharply divided Supreme Court struck down, on First Amendment grounds, F.D.A. rules barring drug companies from advertising "compounded drugs" — drugs specifically tailored to the needs of an individual patient that do not require the elaborate testing process established for new drugs.

The F.D.A. has now invited public comment on whether any of its other regulations raise First Amendment concerns. It's important, however, that the agency not read more into the decision than is there. The Supreme Court made clear that the First Amendment does not protect commercial speech that is misleading, a category that applies to much of the advertising and promotion the F.D.A. regulates. There is nothing in that decision, or any other, to prevent rules against advertising or labeling that misstates the efficacy or side effects of drugs. The court also made clear that narrowly drafted restrictions on marketing of any kind would be upheld if the F.D.A. had a good reason for imposing them.

Critics of the F.D.A. worry that the re-evaluation may be used as a pretext for weakening the agency's oversight just to please the industry. They point to the fact that the agency's general counsel once represented, while in private practice, a conservative legal organization that uses the First Amendment to try to curtail the F.D.A.'s power to regulate drug marketing. Obviously the F.D.A. cannot ignore the court's free-speech concerns. But as it considers its next step, it should also give considerable weight to the voices of public health advocates, who have warned against making changes just for the sake of deregulation or to satisfy someone's commercial interests.