The aim of this study was to determine the frequency of the use of potentially inappropriate medications in elderly patients with gastrointestinal diseases using a comprehensive protocol and also determine the association between identified potentially inappropriate medication and clinical outcomes. Study was conducted from October 2014 to October 2015 at the Department of Gastroenterology of Clinic for Internal Medicine, University Hospital Dubrava, and included patients older than 65 years with the disease of digestive system. For each patient demographic data was collected, data on the treatment prescribed at the hospital, data on primary diagnosis and comorbidities. In the period of three to five months after discharge from hospital patients were contacted by telephone and asked about events after hospital discharge. Potentially inappropriate medications were determined by using a comprehensive croatian protocol, summary of product characteristics (SmPC) was used as a reference source for determining the association between the clinical outcomes after hospital discharge and certain potentially inappropriate medications. The study included 60 adults, average age 74 ± 5,35 (range 65-89) years who have used 7,12 ± 0,45 (range 1-17) drugs and had diagnosed 5,85 ± 0,38 (range 2-14) diagnosis. Comprehensive protocol found that 36,67% of respondents had used at least one potentially inappropriate medication. The most commonly prescribed potentially inappropriate drug was diazepam. For 35% of participant the usage of a combination of drugs that can result in clinically significant interactions was found. The most common interaction was a combination of drugs that act on the central nervous system. The analysis of clinical outcomes after discharge from the hospital shows that 11,67% of the outcomes are associated with the use of potentially inappropriate medications. Although, high incidence of potentially inappropriate medications was identified, the association between potentially inappropriate medications and clinical outcomes was weak.