[en] Aspergillus species are important fungi of the environment, some of them being responsible for severe infections. Many distinct diseases form the human aspergillosis spectrum. The pathomechanisms differ according to the affected organ and the immune status of the patient. The fungus can be responsible for allergic reactions. It may also act as a saprophytic colonizer of air spaces. Infection may remain limited to the skin and nails. It may also be invasive, particularly in immunocompromised patients, in the lungs, paranasal sinus and gastro-intestinal tract. Hematogeneous disseminated aspergillosis represents another dramatic form of the disease.