Haff disease, identified in Europe in 1924, is unexplained rhabdomyolysis i
n a person who ate fish in the 24 hours before onset of illness. We describ
e a series of six U.S. patients from 1997 and report new epidemiologic and
etiologic aspects. Although Haff disease is traditionally an epidemic foodb
orne illness, these six cases occurred in two clusters and as one sporadic
case.