A video purporting to show a man in South Africa downing a bottle of Jägermeister has gone viral online.

The video, entitled "Afrikaner man downs bottle of Jägermeister", was posted to YouTube and shows a man behind a bar drinking the entire bottle in just a few seconds.

The man then dares three others, "Joyce, Gert and Hoffie" to also take part in the challenge.

And now doctors are warning people about the dangers of downing strong drinks over a short space of time.

A litre of Jägermeister contains 35 units of alcohol, the equivalent of 12 pints of Stella Artois.

Dr Martin Prins, a gastroenterologist said: "Your liver is an amazing organ which recovers easily.

"But with something like that, acute or long term damage can cause major problems. Alcohol is toxic for your stomach wall, pancreas and kidneys. It depends on where you're the hardest hit, especially if there are combinations involved."

Some of the videos have been viewed thousands of times, but some have grown sceptical if the subjects are actually downing what they claim to be drinking.

Some have suggested that the bottles are "filled with tea or apple juice and then resealed with prestik."

Dr John-Eduard Bosman, a psychologist suggested that people were doing these videos to help their need for approval, he said: "People around him are egging him on despite the fact that it's not a good thing to do. He would never do it on his own, because what will he get out of it?"

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Health concerns have been raised over the videosReuters