Quality in Herbal Medicines

Herbal medicine usage throughout the world, continues to increase. This growth is due to increased concerns about drug safety, favourable clinical trial results on herbal products, the rising cost of mainstream medicines, and more awareness of preventive and wellness enhancing measures.

It is a fundamental expectation of all consumer products, that the purchaser or user has a right to feel confident that the product contents as stated on its packaging and in marketing claims, are indeed true and accurate.  For medicines especially, this is absolutely imperative, as the stakes can be very high when taking a medicine for a chronic or serious health condition, and taking something different to that which was intended when unwell, can have serious consequences. It is therefore essential, that herbal medicine manufacturers have appropriate systems and procedures in place, to ensure adequate quality assurance can be guaranteed for their products.

When shopping for fresh vegetables and fruit it is relatively easy to assess their likely quality parameters through appraising visible attributes and knowing their source. Knowing that a herbal material was of good quality when it was processed by a herbal medicine manufacturer into a capsule, tablet or liquid preparation, and that such processing incorporated satisfactory standards, is however, very reliant on the manufacturer.

While the majority of herbal products are generally considered safe due to their age-old usage, side effects can occasionally occur. Most of these are mild and due to unpredictable allergic reactions. However, an alarming proportion of adverse effects occur due to insufficient quality of the herbal product itself, including accidental contamination or even intentional adulteration with drugs(1). This is inacceptable in a 2016 or future healthcare environment.

Many instances exist where natural health products have been shown to have contents that are very different to what is stated on their label(2-5). Natural health is a large global business and as with all industries it attracts a small percentage of unscrupulous traders who take advantage of the deficits and sometimes absence of appropriate regulations, to increase their bottom line at any cost.

Biological contaminants (microbes and other organisms) and chemical contaminants (mycotoxins, toxic elements such as heavy metals, and pesticide residues) are the most common contaminants of medicinal herbs and herbal products. Apart from the safety implications, species misidentification and accidental contamination with other plant material or microbes, can often be reasons for lack of effectiveness.QA liquid sampling

In recent years we have seen many instances of low quality Ginkgo biloba extracts being intentionally adulterated with flavonoid compounds from cheaper plants(6). Use of cheaper Chinese and other species of Actaea instead of the true Actaea racemosa species in Black Cohosh products(7), or adulteration or substitution of commercial Berberis aristata and its herbal products with inferior-quality substituents(8), is unacceptably high.

A 2015 analysis of 150 dietary supplements marketed in the U.S. to increase sexual performance, found that 61% of these were adulterated with the drugs sildenafil, tadalafil and vardenafil, and 34% with their structurally modified analogues. Only 31% of the samples could be considered as true herbal/natural products(9). It is perhaps relevant that the U.S. has a relatively lightweight regulatory system in place for so-called ‘Dietary Supplements’, and unlike Australia, Canada and Europe, there is no requirement for ingredients of products sold direct to consumers to first be independently assessed for safety, before being approved for use(10).
Consumers and patients should demand 100% surety that they are taking what is stated and intended, but this will only be achieved with appropriate standards and regulations in
place. To meet these needs, most countries around the world now require natural health product manufacturers to comply with the requirements of what is known as the code of Good Manufacturing Practice, or GMP. GMP is a comprehensive system under which manufacturers should undertake independent tests such as validation of the authenticity and  absence of contaminants for raw materials, tests for pesticide contamination in herbs that have not been grown in certified organic conditions, and microbial and other quality assurance testing on all products prior to them being released for sale. These are reasonable minimum standards that all consumers and patients purchasing and ingesting a herbal medicine or natural health product for their health or medical condition(s), should expect.

New Zealand, however, is now the only developed country in the world not to require GMP certification for natural health product manufacturers, and legislation to introduce some basic standards for the industry, is hugely overdue. While many local companies are voluntarily GMP certified, others claim to have comprehensive manufacturing standards in place, yet most of their products are made using imported raw materials where the supplier’s specification is too frequently accepted at face value, with little in the way of independent checks or tests. This has the potential to cause serious human harm, and damage the local industries reputation and potential in growing offshore markets.

To help prevent potentially harmful effects on consumers taking herbal and other natural health products, and ensure the enormous export potential of the local New Zealand industry is realised, it is imperative that the manufacturing and quality standards included in the forthcoming Natural Health Products Bill, are robust and internationally recognised. New Zealand continues to build a world class reputation for its food and beverage industry sectors, but only upon a backbone of a comprehensive and appropriate regulatory framework. We can do the same for the natural health products industry, but not unless the government is prepared to step up to this now urgent task.


  1. Vaclavik L et al, Anal Bioanal Chem 2014; 406(27):6767-90.
  2. Bateman J et al, Pharmacoepidemiol Drug Saf 2011; 20(10):1104-9
  3. Toomey VM et al, J Pharm Biomed Anal 2010; 59:50-57.
  4. Posadzki P et al, Eur J Clin Pharmacol 2013; 69(3):295-307.
  5. Newmaster SG et al, BMC Med 2013; 11:222.
  6. Avula B et al, Anal Bioanal Chem 2015; 407(25):7733-7746.
  7. Jiang B et al, Phytochem Anal 2011; 22(4):339-351.
  8. Baipai V et al, Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2015; 32(6):799-807.
  9. Gilard V et al, J Pharm Biomed Anal 2015; 102:475-493.
  10. Cohen P, N Engl J Med 2009; 361:1523-1525.

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