Summary: Interstitial pneumonia is an inflammation of the lower respiratory tract that affects the lung parenchyma. Interstitial pneumonia differs from ordinary inflammations by a different course and less severe, non-specific symptoms. These diseases are often characterized by an insidious course, without the presence of characteristic symptoms. Imaging diagnostics and the lack of improvement after antibiotic therapy often contribute to the correct diagnosis. The paper analyzes the factors causing interstitial pneumonia, diagnostics and examples from medical practice presenting various clinical manifestations of this disease.