A 16-year-old teen wanted to lose some weight, so she started drinking green tea that she purchased online. The weight-loss green tea did help her lose a few pounds, but it also damaged her liver, leaving her with hepatitis.

The teen, whose name was not published, went to her doctor complaining of nausea, joint and stomach pains. She was initially diagnosed by the doctor with urinary tract infection and was prescribed with antibiotics. However, things got worse when she turned yellow and was rushed to the emergency room of the Birmingham hospital, the Daily Mail reported.

The girl underwent a series of test to rule out her condition. She claimed that she wasn't taking any drugs or alcohol. However, she admitted that she was drinking three cups of a Chinese green tea a day. She purchased the green tea online and had been drinking it for a few months without any idea of its ingredients.

The doctors diagnosed the teen with acute hepatitis or liver inflammation. They immediately asked her to stop drinking the green tea and gave her intravenous fluids and medications to take until she recovered.

The doctors did not test the green tea, but they believe that it was the drink that caused liver damage to the patient.

"I had only lost a couple of pounds but then started having horrible pains in my joints, and felt very dizzy and sick," she said in the study. "I was very scared when I was admitted to hospital and had lots of tests. I didn't fully understand what was going on at the time."

The doctors clarified that it is safe and healthy to drink green tea. Earlier studies have linked drinking green tea to improved brain function, weight loss, and reduced cancer risk. It could be the unknown chemicals typically used for weight loss that made the drink dangerous.

"I think there are still tons of people who don't realize that because it's natural, doesn't mean it can't hurt you," Dr. Donna Seger, head of the Tennessee Poison Center in Nashville, told ABC News. "They can have very significant toxicity."

Seger is referring to the unlisted herbs or ingredients of the products. She also warned people against buying herbal and weight-loss supplements online.

The case study was published in Sept. 23 issue of the British Medical Journal Case Reports.