The supplements industry has failed to solve one of the most elementary problems involving any medication: guaranteeing that a pure, full strength product is in the bottle.

With prescription and over-the-counter drugs, a complete system is in place. Before approval, FDA chemists analyze the molecule to assure it is a stable structure, and can be consistently manufactured. Each drug has an official chemical recipe-called a monograph-that describes the step-by-step manufacturing process guaranteed to produce a pure drug. Then FDA inspectors inspect the plants to assure the company follows the specified process exactly.

Eliminate the FDA inspection and the result is a voluntary system. A voluntary system is in place, for example, for bottled water. But when the National Resources Defense Council analyzed 1,000 bottles of pure natural spring water and similar elixirs, it found 20 percent did not even meet the safety standards for tap water.

But eliminate the monograph-an official and precise definition of a pure product-and you have almost nothing. To assure purity you must first define purity. The problem is not just theoretical.

Those who have checked actual products found the quality control disaster that must be expected. At Stanford Research Institute International, biochemists analyzed 10 different samples of the human sex hormone, DHEA, widely sold for its alleged anti-aging properties. Three samples didn't contain any identifiable DHEA. Three more samples had at least 25 percent less than claimed on the label. And one sample provided a 50 percent overdose.

Similar results were obtained when the Los Angeles Times sent 10 leading brands of St. John's Wort to an independent lab. It found three products had less than half the potency on the label and seven out of ten failed to meet the standard test of 90 percent of label strength. The sample from Rexall Sundown, a major manufacturer, had only about 20 percent of the labeled potency, the newspaper reported. (The company protested the findings.)

In addition, scientists do not agree about what particular agent in St. John's Wort extract should be measured. Most companies measure a chemical ingredient called hypericin. However, new published scientific findings now suggest that instead, the active agent might be something else, hyperforin.

The problem can be much worse that just getting gypped. Certain babies with an inherited genetic defect will not develop proper muscle strength unless they get the right dose of the amino acid l-carnitine, a dietary supplement.

As a safety check, Meyers' organization for rare diseases asked a Duke University laboratory to check out 12 samples of the drug. With a baby's healthy development at stake, a substandard product becomes just as dangerous as highly toxic contaminant.

One of the twelve products checked had no detectable l-carnitine whatever. Another sample might have contained some l-carnitine. However, since the tablet did not dissolve, even after an hour in a beaker of hydrochloric acid solution, it was essentially worthless. Three more samples provided less than one-half the amount stated on the label.

With herbs and botanical drugs, another quality control problem involves what every gardener and amateur naturalist has learned: Many plants look alike. Could this really be a problem? For example, the foxglove plant looks a lot like the more familiar plantain, a common weed infesting many lawns that is also used as a laxative in herbal products. Foxglove is the original source of one of the first effective, powerful heart drugs, digitalis.

When a young woman developed dangerously irregular heartbeats, the FDA traced the problem to a plantain-based herbal laxative called Chomper, which mistakenly included digitalis. A further check found digitalis in products from seven different manufacturers or distributors, and in bottles at more than one hundred different retail outlets.

The plantain episode was a classic case from the annals of drug safety. The impression was that the situation was under control-until someone started looking carefully. Once investigated, the problem turned out to be everywhere. As in the case of l-tryptophan, steps were not taken to prevent a recurrence or look for similar dangers.

Other botanical quality problems including getting the wrong part of the plant, growing the plant in the wrong place, harvesting at the wrong time of year, or storing it improperly so potency is lost.

So the supplements industry fails the first part of quality control-making sure enough of the good stuff is in the bottle. The second problem is keeping the dangerous stuff out of the bottle. Once again, the available evidence is not reassuring.

It doesn't take a big mistake to create a health hazard, noted Edward Croom Jr., a specialist in medical use of plants at the University of Mississippi. For example, Jimson Weed grows wild in areas where medicinal plants are often harvested. It contains toxic belladona alkaloids. "Probably one leaf in your tea bag, could have physiological effects," Croom said. One likely effect would be hallucinations. "If you had seeds of belladonna, it would take very few."

Anyone who believes these are "natural products" on the shelves needs to look more closely. What they will see is concentrates sold mostly as pills, capsules and powders. Many are synthetic. Others are extracted with powerful solvents, or even created by genetically engineered bacteria (apparently where "natural" l-tryptophan got into trouble).

If they are herbal products, they should be free of dangerous pesticide residues, and any pesticides used should be safe for humans. For lettuce, grapes or other foods, a basic system is in place. Pesticides used on a particular crop for human consumption must be tested and registered with the Environmental Protection Agency, noted Croom. Allowable limits are set.

But for herbal products, Croom said, no pesticides have ever been tested and registered for safe use on herbal or botanical products. That means what is used, how much is used, and whether any remains after processing for human consumption is simply anyone's guess.

Another hazard is heavy metals such as lead, mercury and arsenic. Plants grown beside a busy highway or near an industrial area could easily absorb these compounds, Croom said. Without an enforced quality assurance program, there is no system in place to assure that herbal products are free of these poisons. Is it a problem? Among the five voluntary product recalls the FDA reported in 1998 were three different brands of children's' vitamins. All contained lead.

Croom, who believes medicinal plants offer great benefits to society, said that quality control must involve a certification system that begins when the plant is harvested, and continues through its transportation, storage and manufacture.

So how did consumers get stuck with an entire class of medical products without the essential assurances of purity, potency-and even that the right product got into the bottle? In this case, it's unfair to blame Congress. In largely deregulating the industry in 1994, Congress explicitly authorized the FDA to prescribe quality standards-officially called Good Manufacturing Practices, or GMP.

This looks good on paper. But at a demoralized FDA, with a tiny staff to monitor the entire supplements industry, little has happened. In 1997, three years after the new law, the agency finally published a proposed regulation.

It was written entirely by the same industry that had won freedom from FDA regulation with a legislative campaign of lies. Not a single word was changed. Worse yet, the industry procedures were adapted from the standards used for food processing, not for drugs. So the industry rules focused primarily on issues such as preventing roach infestations, or keeping rats out of the food supplies.

The FDA finally acknowledged that these standards were not workable and appointed a working group to an advisory committee to take testimony and develop proposals. What will result and when remains uncertain. The issue is of great concern to Varro E. Tyler, a senior figure in the science of herbal remedies, and Distinguished Professor Emeritus of Pharmacognosy at Purdue University. (Pharmacognosy is the science of medicinal plants.)

"In this country the biggest problem is the lack of any standards of quality," Tyler said. "The best protection is to purchase a standardized extract from a reliable company. But there are big companies that are lousy and little ones that are lousy, and big companies that are good and little ones that are good."

The failure to control quality is one reason why the safety of dietary supplements cannot be assured. The second safety problem originates in public attitudes. These products' reputation for safety is based largely on myth and fantasy, not scientific fact. These dangerous attitudes are imbedded in the law that exempts these products from the safeguards that are obligatory for most other consumer products with significant health risks.