Singer Amy Winehouse, who was taken to the accident and emergency department of a central London hospital, has been kept in overnight and is likely to be discharged later today.
An ambulance was called to the 24-year-old's house in Camden, north London, and she was taken to University College Hospital.
Police officers were called in to clear a crowd of photographers out of the way to let the ambulance leave Miss Winehouse's home. Miss Winehouse's father Mitch watched her being taken into the ambulance.
She is in a stable condition and Mr Winehouse has remained with her, a hospital spokesman said. She will stay in overnight and medics will take a decision whether to discharge her in the morning.
The singer's spokesman Chris Goodman said: "Amy Winehouse suffered a reaction to medication at her home and was taken to hospital. Doctors have advised that she will be kept under observation overnight and is likely to be released on Tuesday."
The singer has publicly battled with health problems in recent months, with her husband Blake Fielder-Civil's imprisonment causing obvious stress.
She was caught on video in January this year apparently smoking crack cocaine in footage obtained by The Sun newspaper.
The singer spent a stint in rehab before emerging for a well-received performance at the Grammys in February.
Then in June her performances at Glastonbury and the Nelson Mandela 90th birthday concert were thrown into doubt when she collapsed at her home and had to undergo hospital tests.
