My father has just finished his 40 radiation sessions 2 weeks ago and doctor asked to visit after 3 weeks for follow up.. 1 more week to go to visit doctor.. Suddenly he got diarrhea since two days... He has medication prescribed by the doctor for this.. But my question is during radiation and even after 2 weeks everything was smooth.. No diahrea.. But why now? Is it okay to have it at this point?