Lorenzo (Zack O'Malley Greenburg) is a bright and vibrant young boy living in the Comoro Islands, as his father Augusto (Nick Nolte) works for the World Bank and is stationed there. However, when his parents relocate to the United States, he begins to show neurological problems (such as loss of hearing, tantrums, etc.). The boy is diagnosed as having adrenoleukodystrophy (ALD), which is fatal within two years. Failing to find a doctor capable of treating their son's rare disease, Augusto and his wife Michaela (Susan Sarandon) set out on a mission to find a treatment to save their child. In their quest, the Odones clash with doctors, scientists, and support groups, who are skeptical that anything could be done about ALD, much less by laypeople. But they persist, setting up camp in medical libraries, reviewing animal experiments, enlisting the aid of Professor Gus Nikolais (Peter Ustinov), badgering researchers, questioning top doctors all over the world, and even organizing an international symposium about the disease.
Despite research dead-ends, the horror of watching their son's health decline, and being surrounded by skeptics (including the coordinators of the support group they attend), they persist until they finally hit upon a therapy involving adding a certain kind of oil (actually containing two specific long chain fatty acids, isolated from rapeseed oil and olive oil) to their son's diet. They contact over 100 firms around the world until they find an elderly British chemist (Don Suddaby) working for Croda International who is willing to take on the challenge of distilling the proper formula. The oil, erucic acid, proves successful in normalizing the accumulation of the very long chain fatty acids in the brain that had been causing their son's steady decline, thereby halting the progression of the disease. There is still a great deal of neurological damage remaining which could not be reversed unless new treatments could be found to regenerate the myelin sheath (a lipid insulator) around the nerves. The father is seen taking on the new challenge of organizing biomedical efforts to heal myelin damage in patients.
Finally, Lorenzo, at the age of 14, shows definite improvement (swallowing for himself and answering "yes" or "no" questions by blinking) but more medical research is still needed. Ultimately it is revealed that Lorenzo has also regained his sight and is learning to use a computer.
Principal photography for Lorenzo's Oil began on September 9, 1991 in Ben Avon, Pennsylvania.
Possibly to emphasize the "Everyman" aspect of the plot (the notion that a cure could affect families and individuals anywhere), many smaller roles were played by inexperienced actors or non-actors with unusual physical features and mannerisms. For example, the poet James Merrill was noticed by a casting director at a New York public reading of his poetry. His rarefied speaking cadences were utilized in a symposium scene in which he played a questioning doctor.
The film features Allegri's Miserere and Edward Elgar's cello concerto, as well as Barber's Adagio for Strings and Mozart's Ave verum corpus.
The opening song is "Kijana Mwana Mwali" ("Song about a Young Lady"), sung by the Gonda Traditional Entertainers.
A 1960 recording of Maria Callas with the La Scala orchestra and chorus is heard singing selections from Bellini's Norma at several points.
The music for the Easter Midnight Mass scene is a Russian Orthodox Church hymn, "Bogoroditse Devo" (Rejoice, O Virgin) from "Three Choruses from 'Tsar Feodor Ioannovich'", taken from the album Sacred Songs of Russia by Gloriae Dei Cantores.
Lorenzo's Oil was acclaimed by critics. Roger Ebert of the Chicago Sun Times gave it four out of four stars and called it an "immensely moving and challenging movie". He added, "it was impossible not to get swept up in it" and James Berardinelli of ReelViews gave it three out of four stars and claimed, "it was about the war for knowledge and the victory of hope through perseverance." Review aggregation website Rotten Tomatoes retrospectively collected reviews from 32 critics to give the film a score of 95%, with an average rating of 7/10.
Though the film seemed to accurately portray the events related to the boy's condition and his parents' efforts during the time period covered by the film, it was criticized for painting a picture of a miracle cure. Subsequent research with Lorenzo's oil has not clearly proven its long-term effectiveness in treating ALD after its onset, but the oil is highly effective if provided before onset. The actual subject of the film, Lorenzo Odone, died of pneumonia in May 2008 at the age of 30, having lived two decades longer than originally predicted by doctors.
Hugo Moser, on whom the character of Professor Nikolais was based, called the film's portrayal of that character "an abomination".
While a critical success, the film was a financial disappointment taking in $7,286,388 domestically with a budget of around $30 million.
Lorenzo's Oil was nominated twice at the 65th Academy Awards for Best Actress in a Leading Role (Susan Sarandon) and Best Original Screenplay (George Miller & Nick Enright).
Susan Sarandon was nominated for Best Actress in a Drama at the 50th Golden Globe Awards.
The film was nominated for Best Original Screenplay Written Directly for the Screen at the WGA Awards.
Also, the film is recognized by American Film Institute in these lists:2006: AFI's 100 Years...100 Cheers – Nominated