Augusto Odone, who rejected medical opinion and created an oil to save the life of his son Lorenzo has died.
The former World Bank economist died in Italy aged 80, said his family.
Augusto Odone taught himself enough science to invent a treatment for his six-year-old son after he was diagnosed with a neurological disease and given two years to live. Lorenzo eventually died aged 30.
The battle to help him was depicted in a 1992 Hollywood film, Lorenzo's Oil.
Lorenzo Odone was diagnosed with adrenoleukodystrophy, or ALD, a neurological disease that progressively destroys the brains of young boys.
The disease leads to the build-up of dangerous "long-chain" fatty acids, and within a year children are paralysed, blind and unable to speak.
Doctors predicted that Lorenzo would die in childhood.
But Augusto Odone and his wife Michaela refused to accept the prognosis for their son, and put all their energies into trying to find a treatment.
Despite having no formal scientific training, Augusto Odone studied medicine and biochemistry, and concocted a mixture of acids from olive and rapeseed oils.
The Odones eventually persuaded an elderly British chemist, Don Suddaby, to distil the formula, which became known as Lorenzo's Oil.
After testing it on a family member, Augusto Odone gave the oil to Lorenzo, with dramatic results: his long-chain fatty acids started to drop to normal levels.
Its success in delaying the onset of symptoms in Lorenzo was demonstrated by the fact he lived to the age of 30, far beyond what doctors had predicted.
Scientific studies have shown that the oil has most effect on children who have the ALD gene but have not yet displayed any of the symptoms.
The story of Augusto and Michaela Odone was depicted in Lorenzo's Oil, which starred Nick Nolte and Susan Sarandon as the parents.
After the death of his wife in 2000, Augusto Odone returned from the United States to his native Piedmont region of Italy, to be near his surviving children.