Last night, the concert goers were told by loudspeakers to exit the Stockholm arena, which is Sweden's largest. The singer was purportedly taken ill and could not perform, report tabloid media.
"She just couldn't go through with it," said Kristofer Åkesson at event organizer Live Nation to the Aftonbladet newspaper.
Rihanna, 23, is believed to have slept backstage at the arena before being ferried late at night back to her hotel.
She had already cancelled a concert in Malmo on Monday, citing "exhaustion". She then posted an image of herself on the social media site Twitter, showing an intravenous drip inserted in her arm.
The day after she appeared to have made a full recovery and went onto the capital Stockholm. On Tuesday she played for a full house at Globen.