Symptoms are subjective patient experiences that may negatively impact the patient's hospitalization, treatment plan, and quality of life. Critically ill patients frequently experience nausea, vomiting, and diarrhea related to underlying disease, procedures, and medical interventions (eg, medication, enteral feeding, surgery). Optimally, the nurse performs a subjective assessment that explores the patient's perception and impact of these symptoms to develop a comprehensive plan of care. Unfortunately, little evidence is available to guide assessment of nausea, vomiting, and diarrhea in critically ill nonverbal patients. Understanding the disease processes, medical treatments, and pathophysioglogy of these symptoms will assist the critical care nurse in the anticipation of symptoms and development of a proactive plan to alleviate the symptom-associated discomfort.