Over a billion people—both in China and around the world—rely on traditional Chinese medicine (TCM) for their various ailments. Used in the West as a form of alternative medicine, many tout the benefits of the herbs and acupuncture associated with it.
The study, out of the University of Basel in Switzerland, examined the extracts of the plant evodia rutaecarpa, or evodia, as it's more commonly known. The tree produces a fruit that is used in TCM to treat headaches, nausea, vomiting, and even prevent pregnancy.
When researchers isolated the active compounds in the plant, they found that they were highly effective potassium blockers, which can cause serious problems for the heart. When the body's potassium channels are blocked, it can lead to changes in the way the heart beats, or make it stop beating entirely.
They confirmed these results in animal tests, where they observed that only small amounts caused cardiac disturbances in dogs. That means that this ingredient can be dangerous, even if it's a token ingredient in a tea you're drinking.
This shows that these sorts of drugs need to be more tightly controlled: right now, there's very little regulation. A number of teas with evodia have made their way into Europe, and they can also be bought online very easily.