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Assessing the reliability of herbal products

09:52 PM December 08, 2011

In his column last Dec. 5, titled “All about herbal medicines,” Neal Cruz wrote: “You can be sure that each and every herbal being sold by RiteMed has been tested and proven to alleviate, if not cure, the symptoms of some illnesses. Each of them has been approved by the Department of Science and Technology.”

How reliable is that statement? Does testimonial or anecdotal evidence on the effects of drugs derived from plants justify the promotion of their use? Or do we need hard data? One’s health should not be put at risk by claims made by any company, government agency, or persons without adequate proof.


There are easy ways to assess the reliability of claims about herbal products, or of the source person. Find out if a herbal product or a person has published papers in reputable journals, such as those covered in Science Citation Index or SCI (no Philippine journal has met the criteria for coverage in this index). Such journals are accepted worldwide as reliable sources of scientific information. They contain properly published studies on any herbal product or by a person, which can be accessed from PubMed, Web of Science, or Google Scholar (PubMed and Google Scholar are freely accessible). They are the publications that define the herbal product or the expert to trust.

For example, you can search by Google Scholar the list of published papers on lagundi (or Vitex negundo, its scientific name) on studies appearing in SCI-indexed journals. You can also do the same search on a person’s published work. You will see that there are hardly any valid publications on lagundi, which Cruz mentioned in his column. You will only find mostly gray literature (published study without adequate expert peer-review and verification).


The public should trust a herbal product only if there are numerous valid publications supporting its efficacy and safety, and at least one scientific review adequately verifying such results.

At present, there is only one medicinal herbal found in the Philippines, ampalaya (Momordica charantia), on which there are numerous valid publications—over 120 (only two of which are by Filipino authors). Its efficacy and safety have been assessed in a review article. Their conclusion is that placebo-controlled trials are needed to properly assess safety and efficacy before ampalaya can be routinely recommended.

According to the US Commission for Scientific Medicine and Mental Health, there are 29,000 nutritional supplements now marketed in the United States. In 2003, the industry made nearly $20 billion in sales. Federal law now leaves claims about the safety of these products to the scruples of marketers, it says. Many of these products do not give information on the amount of active ingredients.

Do we want this to happen in the Philippines?


retired professor of marine science,

UP Diliman,


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TAGS: health, Herbal Medicines, letters
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