Diarrhea is defecating with liquid concentration or mushy with the defecating frequency of more than three times a day. Based on health research, diarrhea is a disease that becomes the major cause of 31.4% of babies mortality and 15.5% mortality of children under five years old. In the world, as many as six million children die every day due to diarrhea. Death caused by diarrhea is usually caused by continuous defecating so that the patients run out of fluid and electrolite in their body that causes dehydration. The aim of this research was to evaluate the use of diarrhea medicine for patients under five years old at inpatient of Puskesmas Kediri Lombok Barat. This research was conducted in June 2016 using retrospective method which was analyzed descriptive-analytically using cross sectional non-experimental method. The samples consisted of all 81 patients aged 1 -5 years old who were mainly diagnosed with diarrhea during January – December 2014. The result showed that female patients were 49 patients (60.50%), male patients were 32 patients (39.50%), patients who got diarrhea were mostly aged 1-3 years old 67 patients (82.72%), and the type of most frequently used medicine to overcome diarrhea was 81 items (22.5%) of rehydration oralite fluid. It used 81 items of ringer lactate (22.5%) and 81 items of zinc (22.5%). The highest stock of medicine was 109 items (30.3%) of tablets. The route of medication for diarrhea patients was mostly by giving orale medication, with percentage of 77.5%. The suitability of diarrhea prescription was in line with the fixed procedure in Puskesmas Kediri Lombok Barat. The lenght of stay for diarrhea patients was 2.42 days.