Herbal Products Can be Sold as Conventional Foods or Food Additives

Herbal products are complex mixtures that originate from biological sources. Unlike single-entity pharmaceuticals, plants contain thousands of primary and secondary metabolic constituents. In addition, raw materials are inherently variable because their chemical composition depends on factors such as geographical origin, weather, harvesting practices, while the chemical composition of the finished herbal products may not match that of the parent plants, and products frequently contain multiple botanical ingredients.

Herbal products can be sold as conventional foods or food additives

Discussions of exposure to natural products can be complicated by several factors. The first is the market category in which the product falls. Herbal products can be sold as conventional foods or food additives (e.g. flavouring or colouring agents), as dietary supplements, as cosmetic ingredients, or as herbal medicines (various national regulatory schemes may classify these as natural health products, therapeutic goods, phytomedicines, herbal medicinal products, traditional medicines, or conventional drugs). There may also be use of self-collected plants that are not marketed products.

Herbal medicine preparations are herbal products and consequently constitute complex mixtures. The biological impact, and specifically the carcinogenicity of complex mixtures, may be addressed by consideration of information concerning the mixture, and its variability in different contexts, and also by consideration of information concerning biologically active components within such mixtures. Information relevant to possible carcinogenicity may be most adequately addressed with reference either to the mixture or to the active component(s).

Therefore, some Monographs in the present volume are specified with reference to the plant itself, i.e. Aloe vera, Ginkgo biloba, goldenseal, or kava. Other Monographs are specified with reference to individual components known to occur in particular plants, as is the case for pulegone and digoxin. Certain previous IARC Monographs evaluations are immediately relevant to the present evaluations to the extent that they involve components (e.g. quercetin for Ginkgo biloba, anthraquinones for Aloe vera) or metabolites (e.g. phenobarbital for primidone) of agents considered in the present volume.

Herbal products are often derived from intensely processed

Over the past several decades, there has been a revolution in the production, sale, and use of herbal products. In the 1970s, botanicals were largely sifted, cut, or powdered plant material in the form of a tablet, capsule, tea, or tincture. More recently, herbal products are often derived from intensely processed, carefully controlled organic extracts of plant material that have been spray-dried onto a solid carrier or diluent and then formed into a hard or soft capsule or tablet.

The goal of many such processes is to create “standardized” extracts adjusted to contain consistent amounts of selected compounds of interest. Unfortunately, most standardized extracts focus on one or a handful of the thousands of constituents of the whole plant, so that even standardized extracts that are created using different processing techniques (e.g. different solvents, different ratios of plant to solvent) may achieve the desired levels of the desired chemical constituents while being otherwise chemically dissimilar.


Attempts to compare herbal products by viewing the entire phytochemical fingerprint are beginning to appear, but these techniques have not yet had time to have an impact on the market or the publicly available scientific literature (van Beek & Montoro, 2009).