The flu and the common cold have similar symptoms, making it difficult to tell them apart based on just symptoms. Flu symptoms are typically more intense and begin more abruptly than common cold symptoms. Runny or stuffy noses are more common in people with colds than in people with flu. Pneumonia, bacterial infections, and hospitalizations are usually not caused by colds. Complications associated with flu can be serious. Flu symptoms include fever, chills, cough, sore throat, runny nose, muscle or body aches, headaches, and fatigue (tiredness). The symptoms of a cold are usually milder than those of the flu.