Yorkshire Ripper Peter Sutcliffe is said to be near death following a heart attack.
Unconfirmed sources at Broadmoor Hospital reported Sutcliffe has ceased his medication and told a friend: "The situation is bad."
He is said to have suffered a heart attack following a hernia operation.
Sutcliffe, 68, is also said to be suffering from a persistent, hacking cough which has gone untreated. He is apparently worried another heart attack is likely.
The Ripper – who murdered 13 women and tried to kill seven more during what he claimed was a 'mission from God' against prostitutes in the 1970s – revealed his worries to a friend.
He reportedly said: "'Everything is being a struggle, even writing letters has been a big battle – everything's one big effort.
"The situation is bad. I have refused my medication yesterday and today."
An anonymous source told The Sun: "'He's angry with the staff and said he can't go on much more.
'He knows that not taking his medication will cause his blood pressure to go up and he knows how dangerous that is.
"He's said 'I'm not well, I'm not good at the moment.' He's complained dreadfully about things. He thinks they are just not bothered."
A Broadmoor spokesman refused to comment on paranoid schizophrenic Sutcliffe's health.
Ripper Sutcliffe's killing spree lasted from 1975 until he was caught in 1980. He was convicted in 1981 and has spent three decades at Broadmoor, 40 miles away from London.
Sutcliffe's continuing notoriety sees dozens of letters arrive for him each week at the maximum security hospital.