Reports from eyewitnesses said police and ambulance services were seen in the Flotterstone area as well as a helicopter.
Police confirmed they had been called to assist emergency services after receiving reports of a person who had taken ill on Turnhouse Hill just after 10am.
The individual was taken to the Royal Infirmary by ambulance.
A Police Scotland spokesperson said: "Officers were called to assist emergency services partners after receiving a report that a person had taken ill on Turnhouse Hill, near Penicuik, around 10:05am on Sunday, October 25 2020.
"The person was taken to Royal Infirmary of Edinburgh by ambulance."