The 42-year-old had to cancel her Montreal show after she "got suddenly ill" during her sound check, her publicists said.
Jackson was being monitored at an unnamed hospital but no further details of her condition have been released.
- more on this story
Preview and Purchase Janet Jackson CDs
On The Record: The dB's- Rick Monroe and the Hitmen- Atlas Maior- Stoned Jesus
Hot In The City: Lou Malnati's Pizzeria Opens in Surprise, Arizona
What's Doing With Dave Koz? Christmas Carols and Cool Cruises!
On The Record: Craft Recordings Announces Record Store Day Exclusives
Live: T Bone Burnett Rocks Phoenix
Three Days Grace Share First Adam Gontier Reunion Song 'Mayday'
Twenty On Pilots Share 'The Line' From Arcane League of Legends: Season 2 Soundtrack
Motley Crue Dr. Feelgood Pharmacy Independent Retail Takeovers Start Today
Nothing More Scores 3rd No. 1 With 'Angel Song'
Frontiers Rock Festival Returning After 6-Year Hiatus
Bury Tomorrow Unleash 'What If I Burn' Video
Converge Added To Fire in the Mountains Festival
Pop Evil Take Fans On 'Deathwalk' With New Video