Actinomycoses are sporadically occurring endogenous polymicrobial inflammatory processes, in which fermentative actinomycetes of the genera Actinomyces, Propionibacterium, or Bifidobacterium act as the principal pathogens. Difficulties in diagnosing the disease in a timely and reliable fashion have led clinicians and microbiologists to grossly underestimate its medical importance. Therefore, we evaluated microbiological and selected clinical data derived from 1997 culture-positive cases of human cervicofacial actinomycoses examined in our laboratories during 1972-1999. The causative actinomycetes belonged to at least 9 different species, among which Actinomyces israelii and Actinomyces gerencseriae predominated. The well-known predisposition of male patients to acquire the disease varied with age and appeared to be especially pronounced in patients aged 20-60 years, the highest incidence being found in female patients aged 11-40 years and in male patients aged 21-50 years. The relevant procedures necessary for diagnosing human actinomycoses reliably, as well as details of their complex etiology, are discussed.