Licorice tea caused a healthy woman to get high blood pressure and her face and legs to swell up.
The unnamed woman, 49, started drinking the tea to compensate for reducing the sugar in her diet.
An expert said that people who are prone to high blood pressure or pregnant should avoid licorice.
Tea containing licorice caused a healthy women to get high blood pressure and fluid to build up around her face and legs, according to a report.
The unnamed woman, 48, went to the emergency department because she felt "intense fatigue" and had a swollen face and legs, Jean-Samuel Blanpain, an emergency room doctor working at a hospital in Belgium, wrote in a case report published on Tuesday in the Cureus Journal of Medical Science.
According to the report, the woman gained four pounds in four days from the swelling, which started around her eyes.
The woman was hospitalized overnight so doctors could run tests. Blood tests found she had low levels of a hormone called aldosterone, and her potassium was low too.
Aldosterone comes from the adrenal gland and is stimulated by low blood pressure in the kidney.
Too much (not low) aldosterone — typically from a benign tumor in the adrenal gland or medications — causes the body to retain sodium, and with it water that can increase blood pressure and result in feet and ankle swelling. In exchange, the body excretes potassium.
For this reason, the cause of the woman's symptoms and blood tests results didn't initially make sense to the doctors.
The woman told doctors that she drank licorice tea
The doctors discharged the woman the next day. The plan was for her to take potassium supplements and have more tests in an outpatient clinic.
However, four days later the woman went back to the ER because the swelling got worse and her blood pressure had increased.
On this visit, the patient revealed that she'd been drinking licorice tea four to five times a day for three weeks to compensate for her low-sugar diet.
Each tea infusion contained around 0.3 ounces of licorice, according to the report.
Licorice, which comes from a plant and can be found in products ranging from beers and cakes to tea and candy, is 30 to 50 times sweeter than sugar.
There is 'no safe level' of licorice
Jonathan Seckl, a professor in medicine and an endocrinologist at the University of Edinburgh, UK, whose research in 1993 identified an enzyme that explains licorice's "powerful" effects on the kidneys, said that licorice causes high blood pressure and mimics aldosterone.
Seckl told Insider that there was "no safe level" of licorice to consume. He recommended that people who are prone to high blood pressure, or notice their blood pressure increase while taking it, should avoid it — as well as pregnant people.
"It's dangerous in pregnancy because it causes the placental barrier to become porous to stress hormones and has adverse effects on the fetus," he said, citing a study from Finland that found kids aged eight with mothers that consumed licorice during pregnacy had a 10-point drop in IQ.
Her symptoms got better after she stopped drinking the tea
Doctors told the woman to stop drinking the tea that contained licorice, and after 15 days her symptoms resolved.
The doctor shared the report to raise awareness about the negative side effects of licorice.
Read the original article on Insider