He is said to be in a stable condition after he was taken to an unspecified general hospital for treatment.
The child killer recently lost a bid to be moved to a prison Brady was jailed for life in 1966 after he and his partner Myra Hindley were convicted of luring children and teenagers to their deaths.
Some of their victims were sexually tortured before they were buried on Saddleworth Moor.
Last year, Brady, who previously said he wants to starve himself to death, lost a bid to be transferred to prison.
At a mental health tribunal, his legal team claimed he was well enough to be treated away from Ashworth, where staff have a duty to keep him alive by feeding him through his nose.
However, doctors said he was chronically mentally ill and a paranoid schizophrenic who required around-the-clock care.