The aim of the given work is to develop new assessment methods of chronic pancreatitis (CP) clinical course severity and pancreas structural change severity, and using pancreatin as monotherapy and as combination with proton pump inhibitor (PPI), as well as a combination of pancreatin, PPI and NSAID in patients with CP, to figure out the most effective medication treatment way among the ones applied.In given prospective randomized controlled study in order to appraise CP clinical course and pancreas structural change severity, some special methods were developed -Clinical pancreatic index (CPI) and Visual pancreatic index (VPI). In the study CPI and VPI were used for CP patients in case of medical treatment. Patients with CP not needing surgical or endoscopic treatment were divided in three groups, depending on the type of therapy: 1) pancreatin monotherapy group, 2) pancreatin and PPI combined therapy group and 3) pancreatin, PPI and NSAID combined therapy group.The analysis of study approved that CPI is an unbiased and a valid tool to apply for CP clinical course severity and medical treatment efficiency and prognosis assessment. In patients with CP, VPI represents pancreas structural change severity and may be useful for predicting a necessity in surgical treatment. The analysis of study results entitled to conclude that the combination of pancreatin, PPI and NSAID is the most effective in terms of improving CP clinical path and patient's quality of life, compared to pancreatin monotherapy and pancreatin combination with PPI. One month long pancreatin, PPI and NSAID combination therapy is safe for CP patients and does not cause significant side effects. This is the first CP study in Latvia and the world in which 1) the severity of CP clinical course and pancreas structural change severity are assessed integrally and quantitatively, 2) a combination of pancreatin, PPI and NSAID is used and assessed in terms of efficiency, 3) This is the first CP study in Latvia in which EORTC QLQ-C30