This study was conducted at the University of Sofia in Bulgaria using local herbals.

I don’t know the relevance to herbals in other parts of the world, but the results are disturbing.

First, the details.

  • Arsenic, cadmium and lead levels in the following Bulgarian herbs and their infusions were measured using mass and absorption spectrometry.
    • 12 samples of yarrow (Achillea millefolium)
    • 18 of chamomile (Flores chamomillae)
    • 8 of bearberry leaves (Folia uvae ursi)
    • 24 of peppermint (Mentha piperitae folium)
    • 10 of hibiscus (Hibiscus sabdariffa)
    • 14 of oregano (Origanum vulgare)
    • 12 of thyme (Thymus serpyllum)

And, the results.

  • The toxins were present in concentrations ranging from 12-225 mcg/kg arsenic, 15-268 mcg/kg cadmium, 0.2-8.6 mg/kg lead.
  • Arsenic was found in all herbal infusions at levels up to 0.4 mcg/L.
  • Cadmium was present in infusions of chamomile, hibiscus, peppermint and thyme at levels up to 0.7 mcg/L.
  • Lead was detected only in hibiscus infusions (2-3 mcg/L).

The bottom line?
This study takes on added importance in light of the recent report of toxins in Ayurvedic medicines.

It’s not clear if these finding are due to growing the plants in contaminated soil or water, or, in the case of arsenic, due to using pesticides with high levels of arsenic.

Are herbals safe?

Probably most are, although ConsumerLab has reported lead and cadmium contamination in supplements.

It doesn’t happen all the time, but how often is too much?

Here’s what to look for in people taking herbals.

  • Exposure to low levels of arsenic can cause nausea and vomiting, decreased production of red and white blood cells, abnormal heart rhythm, damage to blood vessels, and a sensation of pins and needles in hands and feet.
  • Symptoms of chronic lead poisoning include neurological problems, such as reduced reasoning abilities, or nausea, abdominal pain, irritability, insomnia, metal taste in oral cavity, excess lethargy or hyperactivity, chest pain, headache and, in extreme cases, seizure and coma.
  • Chronic cadmium exposure primarily affects the kidneys and bones. It can also cause cancer. Prevention is the key to managing cadmium exposure. No effective treatment for cadmium toxicity exists.

9/28/08 19:56 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.