As a result, they are not tested for safety or efficacy. Drug companies, on the other hand, must conduct clinical studies to determine the effectiveness of the drugs, safety, possible interactions with other substances, and appropriate dosages. The FDA must review the data and authorize the drug's use before the product may be marketed. The FDA can take regulatory action on an herbal product only after it has received a sufficient number of reports of ill effects and can show the product is unsafe. This system of regulation is always after the fact, not before.
Drug companies have to follow strict quality-control measures.
Herb companies do not. Doses differ between herb capsules and from product to product. An independent test by Consumer Lab in early 2000 found that nearly a quarter of the 30 brands of ginkgo biloba they tested did not have the expected levels of active ingredients. Furthermore, every single product that failed their test claimed it was standardized. The herbal industry is taking steps to address standardization.