Acute Q fever was previously regarded as an uncommon infectious disease in Taiwan but has been increasingly recognized recently. Acute febrile illness, hepatitis, and pneumonia are the 3 most common manifestations of this condition, whereas jaundice is rarely reported among patients with acute Q fever. We report 2 cases of acute Q fever with jaundice and multi-organ involvement. The first patient presented with fever, severe headache, and acute abdomen necessitating laparotomy and was complicated with acute cholestatic hepatitis, acute non-oliguric renal failure and disseminated intravascular coagulation. The second patient had acute cholestatic hepatitis and thrombocytopenia, and the latter was likely related to the infection of bone marrow by Coxiella burnetii, as evidenced by the presence of C. burnetii DNA detected by nested polymerase chain reaction. The incidence and clinical significance of hyperbilirubinemia was also determined by review of medical records of 35 cases of acute Q fever cases diagnosed serologically at National Cheng Kung University Hospital from 1994 to 2001. All had biochemical hepatitis and 23% had hyperbilirubinemia (serum bilirubin > or =2 mg/dL). The febrile course before admission and the period between the initiation of effective medication to defervescence were longer in patients with hyperbilirubinemia than in patients without hyperbilirubinemia, although this difference was not significant. Our results suggest that the predominant presentation of acute Q fever in southern Taiwan is acute febrile illness with hepatitis and that jaundice is not uncommon. Due to the clinical polymorphism of acute Q fever, the threshold of surveys for C. burnetii infections should be low for febrile patients with elevated transaminases or hyperbilirubinemia of unknown cause.