List of products in the National Drug Code with proprietary name . Crofelemer is used to relieve symptoms of diarrhea in HIV/AIDS patients who are taking medicines to treat HIV infection. This medication may reduce the number of watery stools you have and help you better tolerate your HIV medications. It works by preventing water and minerals from entering into the intestines, causing the stools to be more solid. Crofelemer should not be used to treat diarrhea caused by infections.