Colds and flu are actually engendered by the same group of viruses, so their symptoms are interchangeable. The difference, according to Dr. John Hibbs, N.D. of Seattle, WA, lies with the severity and range of symptoms.
Colds can occur at any time of the year and are of shorter duration.
Influenza or flu, on the other hand, develops suddenly and is more severe. It produces fever, chills, fatigue, body aches, even vomiting and diarrhea. The flu usually strikes in fall and winter. Experts agree that not everyone will get sick. They suggest that the key lies with immunity.