Some claim that symptom-based Rome criteria are diagnostic and enhance clinical practice and choice of therapy for patients presenting with gastrointestinal symptoms. This overview focuses on lower gastrointestinal symptoms: constipation, diarrhea, pain and bloating. The main con arguments for using such criteria for diagnosis are: insufficient specificity, overlap of symptom-based categories or disorders, insufficient and therefore non-specific characterization of pain in the criteria, inability to differentiate the "mimics" of IBS-C and IBS-D, and inability to optimize treatment for IBS-M or bloating in the absence of objective measurements. While doctors may not land in trouble using "symptom diagnosis" of IBS, this should not deter them from optimizing diagnosis and treatment of diseases associated with gastrointestinal dysfunction.