How to do herbal research

By fancy graham

There are many types of research out there, many ways to do research and many different things to research when it comes to herbal medicine. For the purpose of this paper I will try to give an outline on how to research scientific studies, herb-drug interactions, and historically or empirically validated research. These are all very large areas that one can immerse oneself into and any one of these subjects can and has filled entire courses, books and websites, but I’ve tried to lay out some basic strategies and resources in an effort to make it less daunting.

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Plant medicine has been around for as long as there have been plants with animals to consume them. There are 5000 year old TCM Materia Medicas that carry extremely detailed information, case studies and specific indications for hundreds of plants, that are used and studied today. Throughout the world, oral tradition and apprenticeship-based learning passed (and continues to pass) herbal knowledge from one generation to the next. Now with the widespread use of technology it is quite easy to access old herbals and clinic notes from a variety of sources. There is also a large and recent body of knowledge specific to many of the physical, emotional, and spiritual problems that exist today. With botany being one of the oldest sciences, scientific research into herbal medicine has been happening for as long as scientific research has been around. Recently, a large part of that research has been done to find plant constituents that can be isolated, synthesized and turned into pharmaceuticals (1). Roughly 25% of all pharmaceuticals contain synthesized versions of plant-derived constituents(2). More recently, there have been scientific studies that try to prove or disprove a plant’s medicinal value or application, and since 1990s the ways in which herbs and pharmaceuticals interact with each other has become the focus of an increasing amount of research.

Scientific studies(3)

There are several databases available online and through university and public libraries (see resources) that you can search to find Randomized Double Blind Placebo Control (RDBPC) studies on humans(4), as well as in vitro studies and in vivo animal studies of plant medicine. Many of them you have to pay for and there are some you don’t. Many libraries (including Vancouver Public Library) have subscriptions to these databases that you can use. It’s important when researching a plant that you exhaust the literature as much as possible and try to read as many studies as you can, because it is often the case that individual studies, when compared, will give opposing or unsatisfying results.

There are many things to look for and questions to ask when doing this research. What are the underlying assumptions of the research (stated, or unstated)? Who wrote it? What do you think their perspective was? Why are they doing the research? Most data can be manipulated to come to a desired conclusion. Who funded it? Most journals require that funders be named. When was the study published? Most research published today is ten years old because it takes a long time to collect and analyze data, and write the article. If it’s a clinical trial, how many people participated? Do the results match similar studies? Who participated in the research? A lot of Allopathic research is done on white men. The first study on women in addiction was done in 1983.

Almost all scientific studies have certain things in common: a descriptive title, an outline of who conducted and published the study, an introduction and background, and a 150 word abstract that is written after the study is done. It is important to read the entire study and not just the abstract. Also included should be a literature review, which generally includes articles and historical references that are relevant to the study, as well as articles that give opposing and supporting research. There should also be enough information on the methodology of the study to be able to reproduce it. It is good to check the references. Do they reference websites? Books? Are the authors of the books or websites Clinical Herbalists, Naturopaths, Doctors, or journalists? what is the ‘p’ value of the study? p< 0.01 = 1 in 100 chances of getting different result.

Other things to look for include, what is the source of the plant being used? The dose? Which part of the plant was used? There are many studies that give an incorrect picture of a plant’s medicinal properties because the study was not done using proper plant parts, with reliable sources for the actual plant, or realistic therapeutic/clinical doses.

There are a lot of scientific studies done in countries like Russia, Japan, China, Germany and Brazil that, if the languages of these countries are accessible to you and the studies are open to the public, you can access them as well. It is also important to note that many more studies take place than the ones that get published. The publishing of a study (or not) can have motivations and some unpublished studies can be found through the Cochrane Collaboration.

In vitro

In vitro (latin for in glass) studies have many limitations, but also have the possibility of providing some useful information. One major thing to consider when looking at in vitro studies is that plants are complex beings with many hundreds or thousands of constituents that interact synergistically, and are metabolized in the body in different ways. In vitro studies eliminate the body’s gut flora, liver, and renal responses so it is very difficult to get a full picture of what a plant would actually do in the body or how the body would metabolize it. To add some words by Jonathan Treasure, “the results of in vitro tests are often contradictory and quite at odds with clinical reality, due to the inherent differences between experimental systems and the in vivo complexities of herbal administration; therefore they have limited predictive value.”(5)

In vivo animal studies

In vivo (latin for within the living) animal studies are a brutal and unnecessary abuse of animals and have no place in the research or study of plant medicine. A long quote by James Green sums it up well….empirically validated universal practice of herbal medicine has not been derived or acquired from the use of animal testing. Many herbalists feel there is no need to validate our science to mainstream medicine, particularly if it requires the harming of animals. We wish to work in a symbiotic relationship alongside mainstream medicine within a reasonable and compassionate health care community, but not at the expense of losing our autonomy and compromising our ethics to prove some sort of legitimacy by someone elses rules. Of equal concern to me are the highly questionable conclusions that research scientists derive based on the vague data gleaned from animal testing. The only consistently reliable information we have accumulated from animal research is that animals have proven to be inadequate surrogates for research on humans. Test values vary dramatically from species to species, even from various strains, sexes, ages, and temperaments within the same species. Reliance on data accumulated from animal testing poses an unacceptable level of risk to human health. It is too often misleading, giving false promises that result in considerable harm to human beings. Only after being tested on living human organisms (in vivo) by many years of clinical observation can anyone truly determine the actual value (and side effects) of any substance in human health care (keep in mind that traditional herbal medicine has already done this.) … testing plant constituents or any substance on non human animal tissue can, at best, only hint to the researcher the direction and extent of the pharmacological activity on human tissue. (6)

Empirical evidence, case studies, journals, talking to your grandma, historical texts, ethnobotany

Most academic institutes believe that they themselves don’t influence their research, and that it is possible to break down and dissect things while maintaining objectivity. The information that is often most available and relevant to herbalists however is empirically or clinically based evidence. This information comes with the understanding that the herbalist’s own experience and values influence how we do our work and what the outcome of that work is.

Empirical evidence and case studies are among the best ways to find clinically relevant information. Before Allopathic or science-based medicine was around to validate, scrutinize or delegitimize herbal medicine, herbalists used their own clinical histories as evidence. The Eclectics, Thomsonians and Physio-medicalists took particularly detailed notes and much of them are available in books, libraries or online. There are also many conferences, lectures and webinars that happen regularly, with the recordings accessible online (see resources).

There is a wealth of information in the minds of our families, elders, neighbours and friends. The grandma that gave you thyme tea when you were sick, or the friendly neighbour that put a mashed up onion on your infected cut, or the elder in the community garden plot next to yours that pushed a ball of leaves in your hands because you were coughing up chunks of phlegm, are but a few examples. This knowledge often goes unrecorded and stays in the minds of the people who hold it.

Every culture or community of people in the world has a history of using plants as medicine and many of the traditional uses of plants cross cultural boundaries. The history of colonization and cultural genocide in this country and the world is long and brutal and ongoing, and as herbalists and healers the work we do can’t be taken out of this context. There are many plants with long and strong ties to the cultural histories of the human communities that grew up around them that grow throughout the world and in the pacific northwest specifically.

There is an unearned sense of entitlement and ownership that persists in north american culture that often leads people to believe that they can use, take, and commodify resources and knowledge from other cultures and communities with impunity. Educating yourself on your own cultural history as well as the different social and political issues that Indigenous and (Im)migrant communities in your area are facing and doing the work to be considered an ally to those communities are ways in which to start deconstructing this sense of ownership and entitlement.

When researching ethnobotanical uses of plants, it is also important to keep in mind that different cultural approaches to medicine/health/wellness can effect how a plant’s medicine is used. Glycyrrhizas use as a harmonizer in nearly every TCM formula while being contraindicated in western herbal medicine for anyone with a tendency to high blood pressure is an example of this.

Blogs, journals, databases, websites and that thing you heard on the internet

There are many herbalists who have dedicated a lot of time to creating and maintaining amazing herbal based blogs and websites that hold huge amounts of information about different herbs, botanical information, clinical uses, case studies, historical and ethnobotanical uses, harvesting, growing, medicine making techniques, recipes, and more. There is also a small handful of websites that have taken it upon themselves to upload, scan or transcribe tens of thousands of pages of old herbal texts and journals spanning the last 600 years or so in many different languages, creating an extremely large and useful amount of information accessible to anyone with computer access (see resources). This is amazing.

With the mainstream marketing and sale of herbal medicine evolving into a multi-billion dollar industry, there is also a lot of inaccurate and misleading information out there as well. Catch phrases like ‘herbal prozac’, ‘herbal viagra’, or ‘herbal magic weight loss’ create a culture of misinformation that has the potential to cause serious harm to the uninformed consumer. Often much of the misinformation circulating about the use of herbs originates from a single poorly done study or a case where herbs were given credit for something that they did or didn’t necessarily do. If you are unsure about the legitimacy of a claim for the use of a plant, it is best to dig deep and look to sources that you trust. Empirically validated sources along with peer reviewed journals and authors or writers that you know are a good place to start.

From Renée Davis’ article “On the Subject of ‘Herbs for Ebola,’” where she critiques information found on social media about herbs to counter the Ebola virus, she ends her essay with these words: “Critically appraise the origins and habitat of information, and be transparent about it. Always look under the hood, because it’s common for people to stretch or sweep away information.”(7)


Herb-drug interactions

There is a lot of misinformation available about herb-drug interactions. While pharmaceuticals often contain a small handful of constituents and their effects on the body are much more predictable, herbs can have thousands of constituents and it is often unknown all the ways in which they affect us. There is a family of enzymes called Cytochrome p450 that is responsible for metabolizing much of what enters our bodies, and understanding this family of enzymes is a good place to start when researching how herbs and drugs interact.

A lot of herb-drug information is based on in vitro studies which often exceed therapeutic doses. There is also no metabolism through the liver or gut flora, so the results often lead to false conclusions. What is shown to be an interaction in vitro, often presents differently when the herb is put into the body in proper therapeutic doses. Once something gets written down it stays in the literature and is cited over and over, so it is not uncommon to hear of an interaction that is taken as truth, only to discover that it came from an inadequate study.

People who are most at risk of interactions are the elderly, people with poor nutritional status to begin with, people taking medications that have a low therapeutic index, people taking multiple medications, and people with clearance issues, such as liver or kidney disease. It is important to note that around 40% of the literature on herb-drug interactions is positive, often including a reduction in side effects and having a synergistic effect. (8)

There are many online databases that can be searched for scientific research on herb-drug interactions as well as a few well-reviewed books (see resources). Medscape (free), natural standard and natural medicines comprehensive database are a few online resources. They are often hyper-cautionary and not clinically based so it is best to be critical, check sources, and reference as many things as you can.


Final thoughts

It is important to remember that as herbalists, we have already done our own research. We have thousands of years of empirically validated evidence that we can draw on and as much as scientific data can be a useful tool for us, it is our own experience, knowledge and histories that show us best how to use plants as medicine. Find some authors, websites, journals, teachers, mentors, etc. that you trust and work form there. Check your sources and their sources and always ask questions.

Question your own lens as well as the people(s) that you’re looking to for information. If something that you think should work for you doesn’t, try to figure out why.


  • is google’s academic search engine and lets you search articles and studies via many different databases and consolidates them into one search engine. There’s a lot to sift through but this is a great resource.
  • The Flower Essence Society. This website is full of information about flower essences, with interviews by practitioners and guidelines about the different ways they perform clinical studies.
  • Paul Bergner’s website has an amazing amount of information. Case studies, clinical tips, in-depth articles, 7 years of free back-issues to medical herbalism journal and more.
  • is a wealth of information. Tens of thousands of uploaded and transcribed pages of old herbal texts and journals from the Eclectics, Physio-medicalists, Thomsonians and a tonne of old european herbals in several different languages. There is so much information on this site, it’s great!
  • The Herbal Research Foundations –
  • Michale Moore’s website – contains thousands of photos and illustrations of plants, as well as thousands of pages of scanned texts from the Eclectics, british herbal manuals, ethnobotanical texts, thousands of pages of his own manuals and so much more.
  • The Commission E monographs can be found at the American Botancial Council’s website
  • PubMed is a free search interface for the MEDLINE database. Many articles cost money but the abstracts are free. and PubMed Central is free.
  • Journal of Ethnobiology and Ethnomedicine
  • is a website that uploads and sells lectures and workshops recorded at a handful of herbal gatherings in the united states. Prices range from 8-40$ per workshop and topics include just about anything.
  • is another website that uploads and sells lectures and workshops by different herbalists.
  • the student journal for the Vermont Center for Integrative Herbalism.
  • Jim MacDonald has a large index of articles
  • Medical Heritage Library –
  • Lloyd Library –
  • “For All Those Who Were Indian in a Former Life” by Andrea Smith
  • is an electronic atlas of flora in B.C.
  • Renée Davis is a clinical herbalist, researcher, board chair of the Olympia Free Herbal Clinic and appointed Associate Scholar with the Center for World Indigenous Studies.
  • Cease Wyss is a Skwxwu7mesh/Sto:Lo/Metis/Hawaiian/Swiss plant picker, grower, and gatherer living in Coast Salish Territory and has a blog
  • Founded by Mélanie Pulla, contains articles and interviews by several different herbalists.
  • Herbal Contraindications and Drug Interactions by Francis Brinkler. Latest edition (4th) is best and includes complimentary positive interactions, is clear about in-vitro/animal/human research, and the appendix is organized by subject of interactions. The book is continually updated and updated information is available online.
  • The Essential Guide To Herbal Safety by Mills and Bone 125 herbs with full monographs. Includes a herb-drug chart for reference.
  • Herb Nutrient and Drug Interactions by Johnathan Treasure. 30 herb monographs, 30+ nutrients interactions , and very detailed/in-depth monographs. Cross-reference in back with drugs.



(1)  Bad link!!!


(3) Much of the information in this section came from a workshop by Carol Geisler called Herbal Scientific Research from the 2014 Midwest Womens Herbal Conference. It can be found at

(4) Explantion on the process and reasoning behind RDBPC studies can be found here.

(5) “Warding off Evil in the 21st Century: St John’s Wort as a Xenosensory Activator?” Jonathan Treasure

(6) Book – The Male Herbal by James Green found on google books.

(7) “On the Subject Herbs for Ebola” by Renée Davis

(8) Much of the information in this section came from a workshop by Jillian Bar-Off called “Herb Drug Nutrient Interactions” during the American Herbalist Guild conference in November 2014. It can be found at

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