Here is a look at how homeopathic drugs differ from conventional medicines and dietary supplements.

Q. What are homeopathic drugs?

A. They are highly diluted drugs made from natural ingredients and sold with explicit claims of medical benefit. They are based on a principle unverified by mainstream science: that substances that create certain symptoms in healthy people are effective in treating the disease that causes the same symptoms.

Q. Who makes sure conventional drugs, homeopathic remedies and dietary supplements are made the right way?

A. The U.S. Food and Drug Administration sets manufacturing standards for both conventional and homeopathic drugs. However, homeopathic products are generally exempt from key requirements, like verifying the ingredients and the amount used.

As for supplements, the FDA in 2007 adopted manufacturing practices that set broad goals for safety and quality of supplements, which are being phased in through 2010.

Unlike conventional drugs, neither supplements nor homeopathic products are normally required to prove they are safe or effective before going on the market.

Q. Are homeopathic remedies and dietary supplements labeled to say what medical problem they treat?

A. Homeopathic remedies, like regular drugs, must state what condition they are designed to treat. Bizarrely, the rules are the opposite for supplements, which are forbidden from claiming to treat a specific condition.

Q. What happens when safety problems arise with these alternative treatments?

A. The FDA may intervene and remove them from the market, as with conventional drugs.