They were carried out of their home on stretchers by an ambulance crew, reportedly suffering from a drugs overdose.
Last night the couple were said to be in a stable condition at Eastbourne Hospital, East Sussex.
An international hunt for their daughter was launched last September after she disappeared with her teacher. The couple were found in the south-west French city of Bordeaux. The girl had been travelling using her mother's passport.
She was reunited with her parents and the teacher was brought back to Britain and arrested on suspicion of child abduction after magistrates in Bordeaux agreed to his extradition.
Neighbours reported that five police cars and two ambulances arrived at the parents' home in Eastbourne, on Wednesday night after the girl's mother rang the emergency services.
In a statement, Sussex Police said: "A man and a woman have been taken to hospital in Eastbourne suffering from the effects of what is believed to be an overdose.
"Police were called to a house just before 8pm last Wednesday. On arrival they found the man described as very ill and the woman who is understood to have called the ambulance service. Both were then taken to hospital."