This is a concentrated form of an herb or supplement, processed to contain a fixed percentage of one or more ingredients. Thus, the ultimate product is said to be standardized to that ingredient.

When you use a standardized extract, you have some reason to believe that one pill is similar in strength to the others. The big advantage of this method is that it allows herbs to be studied in the same kind of rigorous trials as drugs, a necessity if we wish to know for sure whether a traditional herbal treatment really works.

Keep in mind that standardization isn't foolproof. A standardized herbal extract capsule is rated only according to its level of one—or at most, a few—ingredients. Hundreds or thousands of other ingredients may still vary widely from pill to pill. They may vary even more from manufacturer to manufacturer, based on differences in production method, even when the end result has a fixed amount.