In what became known as the "case of the poisoned underpants", two doctors have described how the Reverend Frank Chikane - who now heads the office of President Thabo Mbeki - almost died in 1989 after a special South African military unit slipped a highly toxic substance into his suitcase before he left for a trip to New York.
Mr Chikane, who is not named in the report in The Lancet but described as "currently a senior policy adviser in the office of the President of South Africa", collapsed and had to be admitted to hospital on four separate occasions after wearing clothing taken from his suitcase.
He was sweating, hyperventilating, profoundly agitated, incontinent and vomiting. At one point he stopped breathing and had to have artificial respiration to save his life.
The doctors who treated him - Unnur Steina Bjornsdottir, now a chest specialist in Iceland, and Daniel Smith, of the University of Wisconsin - describe how Mr Chikane recovered each time he was admitted to hospital because he had no contact with the contents of his suitcase. As soon as he was discharged, and started wearing the clothes that had been in the suitcase, he suffered a renewed attack.
The authors have been forced to wait a decade to publish their account to avoid prejudicing a criminal investigation into the assassination attempt in South Africa.
First details emerged in hearings before the Truth and Reconciliation Commission and a subsequent criminal case revealed that organophosphate was put into his suitcase before he left South Africa.
Organophosphates, which are used in some pesticides, range from the relatively benign to highly toxic nerve agents, minute amounts of which absorbed through the skin can cause fatal poisoning.
According to the authors, Mr Chikane later revealed that the South African Civil Corporation Bureau, which masterminded the killing of apartheid opponents in the late Eighties, might have murdered more than 500 people, half of them by poisoning. They say he is the "only known survivor of this organophosphate warfare".
Mr Chikane was lucky because he happened to be in New York, with access to good medical care, when the poison struck. He was taken to hospitalis first while in Namibia but recovered in 48 hours. On his first admission in New York he was diagnosed with acute pancreatitis and on his second, 24 hours later, doctors said he had post-traumatic stress syndrome. Only after the third admission was organophosphate poisoning confirmed by tests.
The authors say that the possibility of organophosphate poisoning had been considered and rejected after the first admission because it was believed there was no possible way in which he might have come into contact with the chemical.
They write: "It is important to remember chemical warfare can be conducted surreptitiously and on a small scale."