Winehouse was at home in London when the incident happened
Amy Winehouse still hopes to perform at the forthcoming Glastonbury Festival and Nelson Mandela concert, despite her ongoing treatment in hospital.
The 24-year-old Rehab singer is undergoing tests after fainting at home on Monday afternoon.
Winehouse is on the bill at the Nelson Mandela gig in London's Hyde Park on 27 June, and at Glastonbury the next day.
"At present she still intends to perform at her two scheduled dates next week," her spokesperson told the BBC.
"However the decision will be made entirely on the advice of her doctors and in her best interests."
"Amy has undergone more scans and tests today and we are awaiting the verdict of her doctors."
There have long been concerns about Winehouse's health.
Last year, she was admitted to a hospital in London suffering from "severe exhaustion", and there were reports that she was being treated in a rehabilitation clinic.
Following a succession of cancelled gigs, the singer's father spoke out about her drug use.
In August 2007, Mitch Winehouse told BBC Radio 5 Live his daughter and her husband Blake Fielder-Civil had "serious problems", but said neither was in "imminent danger of death".
The singer's spokesman has also denied reports claiming she may have tuberculosis.
She had a chest infection and its routine to check for tuberculosis," he said.
"She had a test - it was negative, and shes doing OK. But doctors are still trying out why she fainted."