Interstitial lung diseases (ILD) represent a group of different diseases with similar clinical manifestation and radiological appearance and with different treatment and prognosis according to aetiology. The basic investigational methods in ILD are careful clinical evaluation with emphasis on exposition to environmental and professional antigens, functional investigation, radiological investigation including high resolution CT, bronchoalveolar lavage and usually also lung biopsy. The definitivě diagnosis is made on the basis of the results from all of these tests. Early, precise and careful diagnosis of ILD is necessary because of the different therapeutic approaches required for different ILDs and because the pathologic process in some of them can only be influenced by treatment in the early phases of disease. For this reason it is immensely important that generál practitioners are familiar with the fundamentals of ILDs. ILDs are usually treated with corticosteroids and immunosuppressive drugs, however, more recently, biolo-gical drugs which directly influence the pathway of the cytokines involved in ILD pathogenesis háve been introduced. Long-term oxygen treatment and transplantation of the lungs is considered in the advanced stages of ILDs. Prognosis of ILD is variable and depends on the type of ILD; the worst is for idiopathic pulmonary fibro-sis with a mean survival of 2-3 years from diagnosis.

        Key words: Interstitial lung diseases, differential diagnosis, complex approach, treatment, prognosis