Some of our most important drugs are derived from plants. What would we do without aspirin or digitalis, for example. Before drugs are marketed for humans, though, they must pass rigorous safety and dosage studies. That’s not the case with herbal medicines used as alternative remedies.
We tend to perceive that herbs are innocuous, in part, because we can buy them without a prescription. We in the U.S. spend billions on herbs and supplements, and our use of herbal medicines has doubled over the last decade. However, the potentially toxic effect of herbal remedies on kidneys is increasingly recognized.
Kidneys are the route of excretion of most of the substances present in herbs. The high blood flow rate through the kidneys ensures delivery of large amounts of toxin to the kidneys. As the kidneys do their job of sending water back to the body or out as urine, the toxins become even more concentrated in the kidneys. Studies find several kinds of kidney damage associated with herbal use, including acute kidney injury, chronic kidney disease, hypertension, kidney tubular defects, kidney death, and kidney cancers.
Here is a list of some of the herbs found to harm kidneys:
Herb Kidney Harm
- Chapparal Renal cysts, renal cell cancer
- Ma-Huang, ephedra Nephrolithiasis, obstructive nephropathy
- Djengkol Nephrolithiasis, obstructive nephropathy
- Star fruit Nephtolithiasis, obstructive nephropathy
- Cranberry Nephtolithiasis, obstructive nephropathy
- Licorice Hyperkalaemic nephropathy
- Willow bark Renal papillary necrosis
- Yohimbe Lupus nephritis
- Bladder wrack Chronic interstitial nephritis
- Rhubarb Chronic interstitial nephritis
- Coneflower Renal tubular acidosis
- Aristolochic Acid (AA) Chronic kidney disease
While we may not be familiar with all the names listed above, these herbs are commonly used in herbal medications. For example, AA is a component of birthwort and is a well-researched kidney killer. This kidney-toxic herb sometimes is mixed with other non-toxic herbs and not separately identified. AA is commonly used in traditional Chinese medicine.
Not really an herb, synthetic marijuana, called “spice,” causes almost immediate kidney injury. Several cases recently occurred in the Pacific Northwest.
The NKF provides listings of damaging herbs, some surprising. Take a look: NKF’s Kidney-Damaging Lists of Herbs.