My 75 y/o mom was prescribed lactulose to replace her imodium. Her stool cultures came back negative. I am confused about why he would want her to take lactulose..Help! She was having 2-3 very runny, mushy stools daily. We controlled her diet, stopped all dairy products, tomatoes, nuts, anything we thought might be causing the diarrhea. Her Dr. first had her take imodium, but she was still having diarrhea so now that her cultures came back negative he prescribed 15ml BID.