My 18 year old son is dealing with lower abdominal/gas type pains combined with diarrehea and constipation. It s gotten to be a yo-yo with taking immodium to slow down his movements and then he gets plugged up. He has just gone off to college and I can t get him to our doctor as easily and I don t want to scare him, so I have tried to get him on a twice daily probiotic thinking we may be dealing with IBS. A week in and he s not feeling any better. There s no blood in the stool and no nausea and it turns out it s been going on for the better part of 6 months or so and he just hasn t told me anything.