Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent fever of unknown origin, renal amyloidosis, peritonitis, pleuritis and/or synovitis. There have been many studies to elucidate the etiopathogenesis of FMF. IL-6 is a cytokine that can induce the formation of serum amyloid A and C-reactive protein, both of which are important in development of amyloidosis. IL-6 was determined to be strongly associated in the etiopathogenesis of periodic fever in Chinese-pei dogs. The dogs with this syndrome experience periodic fever, arthritis, renal amyloidosis, a clinical picture very alike of human FMF. Here, we aimed to study mainly whether IL-6 had a similar etiopathogenetic role in human FMF as in Chinese-pei dogs syndrome. The median IL-6 blood levels were found to be higher in patients with acute (n=8) FMF attack (1.85 U/ml) compared to those (n=33) with asymptomatic ones (1.0 U/ml) (p=0.16). There are mainly two results: first; the study should be designed with a larger sample size of patients with acute attack in order to alleviate underestimation of significance, second; sampling time may give various results because of dynamic changes of cytokine levels during acute attack period.