Plant Detective, The

Monday 3:58 PM and Saturday 6:00 PM

Each week Flora Delaterre a.k.a. The Plant Detective investigates a new medicinal plant somewhere around the globe--and it could be in your backyard. Beth Judy writes and voices this minute-and-a-half program in consult with Bastyr University, Tai Sophia Institute, and the Vermont School of Integrative Herbalism. Produced by MTPR. Podcasts available on this website as well.....

Flickr user, Nuuuuuuuuuuul

Modern interest in mistletoe as a possible treatment for cancer began in the 1920s. For centuries, it had been used as something of a cure-all, but when mistletoe's immunostimulant properties were confirmed, the Druids' reverence for the healing power of this parasite got some scientific validation. Since then, lots of studies have been done in Germany, where many cancer patients augment conventional treatment with mistletoe extracts. In the lab, it kills certain cancer cells, while boosting the number and activity of white blood cells.

Flickr user, free photos

Mistletoe, a parasitic plant that grows on a wide range of host trees, shows up on every continent but Antarctica - and on each continent, it's been used in folk medicine. From ancient Greece into twentieth-century America, it was prescribed for epilepsy. Over the centuries, healers have used mistletoe to treat arthritis, menstrual problems, miscarriage (through controlling bleeding), hypertension, and pain - and that's just the short list. It's prescribed frequently in Europe. But don't try any of these uses without a trained health practitioner, because mistletoe can be toxic.

Flickr user, Audrey

Passionflower is a beautiful climbing vine native to the Americas whose corona reminded people of the crown of thorns worn by Jesus during his crucifixion. It's a sedative, milder than valerian or kava - often, you'll find it used in combination with other calming herbs like lemon balm. Passionflower calms the nervous system, reduces anxiety, and soothes insomnia and muscle spasms. Scientists think it increases levels of gamma aminobutyric acid (GABA) in the brain. Don't use passionflower if you're pregnant or breastfeeding; it's a uterine stimulant that can over-sedate your baby.

Franz Eugen Köhler

The Efik people of the region that is now Nigeria used to force people accused of crimes to suffer a trial by ordeal: they'd be fed calabar beans, a known poison. If the accused died, they were judged guilty. If they lived, they were "proven" innocent. There's some pharmaceutical basis to this. It turns out that the poison of the calabar bean is absorbed in the mouth, where a guilty person might try to hold the beans, to avoid swallowing. For the guileless who swallowed them whole, the emetic properties of the beans might cause them to throw up the beans and escape poisoning.

Flickr user, Kirill Ignatyev

You might have brushed by it in the forest, where this hairy-looking symbiosis between algea and fungi perches on tree limbs. The look of the lichen usnea explains its nicknames: "old man's beard," "tree's dandruff," "women's long hair," and "beard lichen." For centuries, it's been considered a handy medicinal. People grab some to dress wounds, or take it internally for infections or oral inflammation. But in the 1990s, when manufacturers of weight-loss drugs started adding sodium usniate (usnic acid) to their formulas, several cases of liver damage emerged.

Flickr user, Marilylle Soveran

It's not an old wive's tale: cranberry helps prevent and treat urinary tract infections. And it's not just the acidity: a compound in cranberries and blueberries keeps bacteria from sticking to bladder and urinary tract walls. Cranberries are high in several kinds of antioxidants, including proanthocyanidins, which give the ripe berries their vivid red color.

In the 1672 book New England Rarities Discovered, author John Josselyn described cranberries:

Flickr user, Jon Bunting

Among the artifacts discovered in the tomb of Egypt's Tutankhamen - objects meant to ease the boy king into the afterlife - were 3,000-year-old bulbs of garlic. Giving as well as receiving, Tut supplied daily rations of garlic to his pyramid-building slaves, for endurance and health. Garlic is a fabulous heart helper: its blood-thinning and anti-clotting abilities may slow down atherosclerosis and lower blood pressure.

Flickr user Mark Robinson

Ever since nomadic tribes helped spread wild garlic from Central Asia to far-flung parts of the globe, garlic has helped humans fight microbes. Louis Pasteur recognized its antimicrobial power, as did doctors in WWI and WWII battlefield hospitals, where injured soldiers were given garlic to prevent infection and gangrene. Today's warnings of a "post-antibiotic" future mean garlic's power may turn out to be handy as drug-resistant bacteria become widespread.

Flickr user, Kent McFarland

In 1905, author Harriet Keeler wrote about the inner bark of the slippery elm tree: “It is thick, fragrant, mucilaginous, demulcent, and nutritious. The water in which the bark has been soaked is a grateful drink for one suffering from affections of the throat and lungs.”

David Dickerson

Medicinal use of datura - also known as moonflower - is so ancient, no one is sure where the plant originated. Two important nervous system depressor drugs, atropine and scopolamine, are derived from it. Oracles in the Americas and Greece used it for divinations. Witches in medieval Europe applied it to their skin in ointments. And when modern-day researchers experimented (a risky proposition; one of the researchers died) with those old witches' recipes, they reported intense dreams of flying. Broomstick, anyone?


The alkaloid atropine occurs naturally in plants like deadly nightshade, datura, and henbane. It can keep your heart rate steady after a heart attack, dilate your eyes - think belladonna - or dry up secretions during surgery. Soldiers carry atropine injectors because it's an antidote to nerve gas. But in high doses, it's hallucinogenic and poisonous. Remember the three fates of Greek mythology? One of them, Atropos, determined the mechanism of death for mortals. Atropine is named for her.

Henri Pidoux © CITES Secretariat

The powerful anti-inflammatory action of harpagoside, a compound in the roots of devil's claw, relieves the pain of osteoarthritis, and many herbalists recommend it for digestive problems. The San of the Kalahari have used it medicinally for centuries. But because devil's claw is gathered wild from the deserts of Southern Africa, where the tubers are an important source of income, there is pressure on the population. In some regions, the current rate of harvest might not be sustainable.

Flickr user, Kai Hendry

This feathery plant from the deserts of Afghanistan and the mountains of Iran stinks - until you cook it, that is, when its pleasant flavor and active antiflatulent and digestive properties emerge. You can find it in Worcestershire sauce and throughout South Indian cuisine as a flavor enhancer and digestive aid. Devil's Dung is also antimicrobial.

(Podcast: "The Plant Detective")

Antiflatulent, helps digestion.

Flickr user, Pfly

The gigantic leaves of devil's club barely hide its sharp thorns  - if you're ever sliding down a mountain slope, this is not a plant to grab. But inside the roots' bark lies medicine for all sorts of evils: native coastal North Americans treated as many as 34 types of ailments with it.

Flickr user, Ali Graney

The causes of migraine aren't well understood. Neither is the mechanism behind feverfew's proven ability to stop or prevent a migraine headache. Feverfew supplements used in clinical studies to treat migraine contain a standardized dose of 0.2 to 0.35% parthenolide, so if you research this herb, pay attention to dosage details.  Pregnant women and children under the age of two shouldn't use it, and people with allergies to ragweed, chamomile and yarrow are sometimes allergic to feverfew.

Goldenseal II

Sep 13, 2014

Goldenseal (Hydrastis canadensis) grows in eastern North America, where it's now threatened in the wild. An alkaloid in goldenseal, berberine, shows powerful antimicrobial effects against a wide range of bacteria, yeasts, and parasites. Herbalists prescribed goldenseal to stimulate the immune system, fight infection, and treat diarrhea.

(Podcast: The Plant Detective, 9/13/14)

Goldenseal I

Sep 6, 2014

There's a persistent urban legend concerning the herb,  goldenseal: take it before a urine test and you'll get false-negative results for a variety of recreational drugs. Disappointingly for those who try, goldenseal won't mask drug residues in the blood. The idea came from Stringtown on the Pike, a novel published in 1900 by plant pharmacist John Uri Lloyd. In the book, goldenseal causes a false-positive result for strychnine poisoning.

(Podcast: The Plant Detective, 9/6/14)

Mexican Yam

Aug 30, 2014

In the 1930s, scientists trying to synthesize estrogen and progesterone for therapeutic uses - and possibly to create a new kind of contraceptive - faced an obstacle: they needed an abundant, cheap source of the hormones for mass production. Chemist Russell Marker discovered a way to extract progesterone from plants, and began searching for one that could yield enough of the hormone. After searching for a decade, he found it: the wild Mexican yam.

(Podcast: The Plant Detective, 8/30/14)

Tea Tree

Aug 23, 2014

Indigenous Australians use the twigs and leaves of the melaleuca (tea tree) medicinally, and science has confirmed the tree's antimicrobial, antifungal, and antiviral properties.  Tea tree oil is used topically to treat a range of skin infections, cuts, burns, insect bites and stings. A 2012 review by the National Institutes of Health found that "a 5% tea tree oil gel appears to be as effective as 5% benzoyl peroxide" for treating mild to moderate acne.

(Podcast: The Plant Detective, 8/23/14)


Aug 16, 2014

In southern China, where Camptotheca acuminata is native, people call these big-leafed trees "Happy Trees." Chinese herbalists have been prescribing medicine from the leaves for centuries to treat various ailments, including leukemia. In the 1950s, National Cancer Institute researchers in the U.S. isolated the alkaloid camptothecin from the leaves, and today, several drugs derived from camptothecin help treat ovarian and colon cancer.

(Podcast: The Plant Detective, 8/16/14)


Aug 9, 2014

Ever since people in tropical regions around the world began to grow Madagascar periwinkle (Catharanthus roseus) for its cheerful pink flowers, the plant has been known as a home remedy for diabetes. In the 1950s, when researchers began testing periwinkle for its anti-diabetic properties, they discovered several highly toxic alkaloids in the plant's tissues. Two of them led to key drugs for cancers of the blood: vinblastine and vincristine.

(Podcast: The Plant Detective, 8/9/14)

Nettle II

Aug 2, 2014

In the National Museum of Denmark, there's a 2,800 year old piece of Bronze Age cloth made from nettle fiber. Nettle fabric has been used a lot more recently: in the early 20th century, when Britain controlled India's supply of cotton, Germany and Austria got busy developing nettle as their own source of fabric. During World War I, German uniforms were made of it. Nettle can produce fabric dye, too. In the 1990s, German botanists re-discovered earlier research into high-fiber nettles, and today, various European clothing manufacturers specialize in nettle fabric clothing.

Nettle I

Jul 26, 2014

It's not called "stinging nettle" for nothing: if you're going to spend time in a nettle patch, cover up. The hairs on nettle's leaves and stems are miniature hypodermics, waiting to pucture your skin, which - ouch! - stings, then burns, then aches. But on arthritic joints, that sting stimulates, then exhausts, the production of pain messengers to the brain. Nettle leaf soup (cooking neutralizes the sting) has been found to reduce pain and immobility in people suffering from rheumatoid arthritis.


Jul 19, 2014

When taken as herbal medicine, echinacea stimulates our immune systems, raising white blood cell counts and strengthening cell walls. Although it originated in North America, where native Americans used echinacea as something of a cure-all, in the 20th century, Germany is where its popularity first surged. People use echinacea to shorten the duration of the common cold and reduce the symptoms, and to boost immunity and fight off upper respiratory infections.

Asian Ginseng

Jul 12, 2014

7/12/14: This week on The Plant Detective: Asian ginseng, Panax ginseng, helps people with Type 2 diabetes maintain healthy blood sugar levels. Both Asian and American ginseng contain ginsenosides, just in different proportions. Asian ginseng stimulates while American ginseng calms, and in the terms of Chinese traditional medicine, Panax ginseng promotes yang energy and cleans excess yin. American ginseng (Panax quinquefolius) does the opposite.

Tea II

Jul 5, 2014

7/5/14: This week on The Plant Detective: They may have different flavors but black, green, white and oolong teas all come from the same plant: Camellia sinensis. They're just processed differently; black tea is fermented, green tea isn't. Unfermented green tea is especially high in catechins, those antioxidants that scavenge the blood for free radicals and are associated with lower rates of atherosclerosis.

Tea I

Jun 28, 2014

6/28/14: This week on "The Plant Detective:" According to archaeologists, human use of tea,  Camellia sinensis, goes back 500,000 years.  The flavonoids in tea are more effective antioxidants than Vitamins C or E - they seem to boost immunity and protect against cavities and ultraviolet rays. More research is needed to find out if tea's flavonoids protect against cardiovascular disease and certain kinds of cancer.

American Ginseng

Jun 21, 2014

6/21/14: This week on "The Plant Detective:"  Even today, many elderly Chinese still prefer a good ginseng root to health insurance. American ginseng (Panax quinquefolius) is used to aid digestion, treat diabetes, boost immunity, and balance qi, or life energy.


Jun 14, 2014

6/14/14: This week on "The Plant Detective:"  Aloe was one of the most frequently prescribed medicines throughout most of the 18th and 19th centuries. It remains one of the most commonly used herbs in the United States today, protecting against ultraviolet rays, relieving the pain of minor burns - and sunburn -  and helping skin regenerate. One study found that aloe vera gel displayed anti-inflammatory effects superior to 1% hydrocortisone cream or a placebo gel.


Gotu Kola

Jun 7, 2014

6/7/14: This week on "The Plant Detective:" For thousands of years, people in India, China, and Indonesia have used gotu kola to heal wounds, improve mental clarity, and treat skin conditions such as leprosy and psoriasis. Today, in the U.S. and Europe, gotu kola in ointment helps heal minor wounds and taken in other forms, it treats varicose veins and chronic venous insufficiency. The Chinese use it to reduce stress.

Don't confuse gotu kola with cola or cola nut. They're completely different plants.