Rihanna is said to be 'exhausted' as she cancelled a second show in Sweden an hour before she was due on stage.
The singer, who is on the final leg of her Loud tour, was due to play in Malmo, Sweden last weekend when she was taken to hospital and hooked up to a IV drip.
A Live Nation spokesman stated that the S&M singer 'is exhausted and doesn't feel well.'
Organisers are currently trying to arrange new dates for the shows that have been cancelled.
Doctors have reportedly told the singer that she needs to take it easy and calm down the partying, according to The Sun.
A source told the newspaper: 'Rihanna is running on empty but she's still been going out drinking and living it up,' a source told the publication.
'She doesn't have any down time where she can completely relax. She spends most of her time in the studio, on stage or in clubs. Doctors are worried she's overdoing it. She needs to take some time off. Otherwise she'll be vulnerable to more illness.'