The TV presenter, 65, was seen by an on-site medical team before being admitted to hospital as a precaution, ITV said.
Wednesday’s episode of the show saw Madeley slide head first into a sewer of rotten fruit and vegetables during a trial called Castle Kitchen Nightmares.
The challenge saw the presenter hunt for 10 hidden stars in a room ;full of castle critters’ as rotten food was dumped on him from above.
An ITV spokesman said: ‘Richard was unwell in the early hours and was immediately seen by our on-site medical team.
‘He’s since been taken to hospital as a precaution, the health and safety of our campmates is our priority.’
A spokeswoman for the Welsh Ambulance Service said: “We were called at 05.43am this morning, Thursday 25 November 2021, to reports of a medical emergency at Gwrych Castle in Abergele, Conwy.
“We sent a paramedic in a rapid response car and an emergency ambulance to the scene, and one patient was taken to hospital.”
The flagship series is returning to Wales for a second year because of ongoing coronavirus travel restrictions, preventing filming at its usual Australian jungle location.