The submitted investigation deals with the value of assessment of selected reactants of the acute stage in patients with acute pancreatitis and their follow-up in the course of the disease. For the investigation C-reactive protein, alpha-1-antitrypsin and haptaglobin were selected. In addition to the prognostic impact the authors focused attention on assessment of the dynamics of individual proteins and their importance for the early detection of complications in acute pancreatitis with different etiologies. The high CRP level on admission of severe cases of pancreatitis--mean 166.9 mg/l (range from 100 to 320 mg/l)--correlated with other signs suggesting severe pancreatitis and the latter was confirmed by computed tomography (CT), surgery or post-mortem examination in 90% of the patients with a CRP level above 100 mg/l. This correlation was not confirmed for alpha-1-antitrypsin or haptaglobin.