A medical evaluation is usually important. Related StoriesFDA grants accelerated authorization for Tagrisso to take care of sufferers with advanced NSCLCMD Anderson research reveals why chemotherapy medications not effective for most pancreatic malignancy patientsCornell biomedical engineers develop 'super natural killer cells' to destroy cancer cells in lymph nodes6. Alter in bowel behaviors Mild diarrhea that lasts more than a full week, constipation that lasts a lot more than two weeks, or unexplained, sudden urges to get a bowel movement are reasons to consult with a doctor. Also on the list are bloody diarrhea or stools that are dark or tar colored. These symptoms could derive from infection, medication unwanted effects, a digestive colon or disorder cancer.