One Species’ Upper May Be Another’s Downfall
The Washington State Department of Agriculture wants people to know that a popular mood-elevating drug has a downside.
It causes cows, sheep and horses who eat it to lose weight and sunburn.
The Washington Department of Agriculture issued a warning last week that St. John’s wort, both a toxic weed and a popular herbal anti-depressant, has “a dark side.”
An extract of the weed, hypericin, has been used for centuries as a mood-elevating drug. And lately it has been touted as a weight-loss supplement. Lauded for its benefits, the weed still makes livestock that eat it more sensitive to light.
“It’s a photosensitization that causes lesions on the animal’s skin,” said Dr. Robert Mead, the Washington state veterinarian. Though they usually avoid the weed, if animals can find nothing else to eat, they will graze on the flowering plant. Enough of the plant will cause them to develop dermatitis, skin blisters and hair loss, Mead said.
“It looks like a sunburn-type lesion,” said Patricia Talcott, veterinary toxicologist at the University of Idaho and at the Washington Animal Diagnostic Disease Laboratory. “It typically affects the light area of the skin. With sheep it’s usually around the face.”
While it may harm animals, many medical experts are saying the plant helps humans. German doctors have prescribed dosages of St. John’s wort as an anti-depressant for hundreds of years. And though it has been in the U.S. market at stores for more then a decade, only recently has its U.S. popularity soared.
Also called Klamath weed, goatweed or hypericum perforatum, St. John’s wort is a perennial plant carried from Europe by colonists over a century ago. Farmers, ranchers, scientists and weed boards have worked for years to control the plant, which is invasive and often displaces native plants.
Even though the plant is scattered throughout the region, few if any animals in Washington and Idaho have been diagnosed with exposure.
“I have never documented a case myself,” said Talcott. “In fact, I haven’t seen a documented case in the (veterinary) literature for the last seven years.”
But as Washington and Idaho farmers consider growing the weed to sell for use in homeopathic drugs, the WSDA cautions growers about its dangers and encourages them to take actions to contain it.
“If they’re going to grow it, they need to have some type of adequate containment like buffers in their fields. And they need to take care transporting it.” said Greg Haubrich, weed specialist at the WSDA. “We are encouraging them to be careful and to understand there is a dark side to St. John’s wort.”
Idaho entrepreneur Terry Foley is working with 30 farmers in northeastern Washington and North Idaho to raise about 2,000 acres of St. John’s wort in 1998. He said the farmers are aware of, but not worried about, the hazards of the weed.
“We have set out very specific guidelines for them,” he said. “We know enough about the plants to put it in the field commercially. In a managed environment, it’s not like it is out in the wild. I think the noxious weed boards know that.”
To encourage responsible growing of the weed, the WSDA requires farmers to get permits from their county weed boards.
“The plants are very attractive,” said Linda Waring, spokesperson for the WSDA. “But we wanted to make sure that people understood they are noxious weeds.”