After years of controversy, the unorthodox treatment that inspired the1992 film Lorenzo's Oil has been shown to work. Lorenzo Odone was five years old when he first developed symptoms of the rare genetic condition adrenoleukodystrophy (ALD). He was given two years to live. Determined to find a cure, his parents delved into the medical and scientific literature, and came up with 'Lorenzo's oil', a mixture of oleic and erucic acids. At 24, Lorenzo is still alive today, but the medical community has always been sceptical about whether the oil actually works.

Hugo Moser of the Kennedy Krieger Institute in Baltimore recently unveiled the findings of a ten-year trial of the effects of Lorenzo's oil in boys with early-stage ALD. The oil reverses the main biochemical abnormality of ALD — the accumulation of very-long-chain fatty acids. This study confirms that it can also markedly reduce the chances of developing the devastating neurological symptoms, which reflect a progressive loss of myelin.

According to Ian Duncan of the University of Wisconsin, the consensus among specialists is that “this is an extremely important finding ... [most specialists] now acknowledge that this therapy can work” (The Guardian, UK, 15 October). But the timing of treatment is crucial. “Give the oil as soon as you know your son carries the genetic defect. If you wait, the symptoms might come and then you are in a different ballpark”, Lorenzo's father, Augusto Odone, told the New Scientist (UK, 26 September). “It's not the final cure of the disease”, says Ronald Wanders of the University of Amsterdam, “But it at least gives additional time to come up with alternative therapies” (USA Today, 22 October). In the meantime, Moser says, “it's important that we let families and the scientific community know that this positive response has been observed”.