Reye syndrome, characterised by the combination of liver disease and noninflammatory encephalopathy, is a non-specific clinicopathological entity and a descriptive term covering a group of heterogeneous disorders. Nowadays, some of these patients are diagnosed more correctly as having infectious, metabolic, toxic or other disease. The non-specific case definition implies that the epidemiological studies suggesting a link with acetylsalicylic acid have been performed on a heterogeneous group of children, whereby the value of these studies and their ensuing hypothesis is weakened. Moreover, a detailed analysis of the epidemiological surveys of the Centers for Disease Control, the Yale study and of the British risk factor study provides evidence that not only the use of acetylsalicylic acid but also that of phenothiazines and other anti-emetics is significantly greater in Reye syndrome cases than in controls. As to the decline of Reye syndrome, recent literature data reveal that this is related to more accurate modern diagnosis of infectious, metabolic or toxic disease, reducing the percentage of idiopathic or true cases of Reye syndrome.
Conclusion: Reye syndrome is a non-specific descriptive term covering a group of heterogeneous disorders. Moreover, not only the use of acetylsalicylic acid but also of antiemetics is statistically significant in Reye syndrome cases. Both facts weaken the validity of the epidemiological surveys suggesting a link with acetylsalicylic acid.