A man was taken to Ninewells Hospital after a medical incident near Slessor Gardens.
Police and ambulance personnel were pictured on South Marketgait at around 11pm on Thursday.
A spokesman for the Scottish Ambulance Service confirmed the man was taken to Ninewells.
One man who had seen the emergency services at the scene said it was a “concern” to see what was unfolding.
He added: “I’d not long left one of the nearby pubs and was heading home and saw the person on the ground.
“There were members of the public there along with police and the ambulance crew.
“I saw they had put foil around the person to keep them warm.”
A spokesman for the Scottish Ambulance Service added: “We received a call to attend a medical incident on South Marketgait in Dundee.
“We dispatched one crew to the scene and transported one male to Ninewells.”