Amy Winehouse was released from a London hospital after an overnight stay.

The 24-year-old singer-songwriter was discharged from London's University College after spending the night in observation, said spokesman Chris Goodman.

Winehouse was rushed to the hospital's emergency room with what her spokesman said was an adverse reaction to medication.

Goodman said the medication had been taken at her home, but did not provide further details.

"She had a bit of a scare yesterday because of a reaction to treatment. She was kept in overnight purely for observation," Goodman said in a statement.

"Amy is at home now after leaving with her father and manager. She is having a rest."

Amy Winehouse, as her father, Mitch Winehouse, said at the time, had developed early stage emphysema from smoking cigarettes and crack cocaine.

Winehouse was investigated by police after a tabloid newspaper published a video that appeared to show her smoking crack cocaine.