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Flu Symptoms

Influenza, the "flu," is a highly contagious infection of the respiratory tract that can cause fatigue, muscle aches, fever and chills. The flu IS NOT just a severe cold, but a different infection caused by a different virus.

Get the Basics on Influenza (Flu)

  • blue woman with thermometer in her mouth; cold symptoms; flu symptoms
    Influenza (Flu)
    Flu can be mild or severe depending upon the type of virus, your age and overall health. Flu can affect many body systems, making you feel sick all over.

The Flu Can Wipe You Out

  • woman lying down; feeling ill, malaise, fatigue
    Weakness
    Weakness may be subjective (feeling weak with no measurable loss of strength).
  • tired man rubbing his eye; fatigue, drowsiness, flu symptoms
    Fatigue
    Fatigue is a feeling of weariness, tiredness, or lack of energy and motivation.

The Flu Can Hurt

  • massage, alternative therapy, complementary therapy, pain relief, stress relief
    Muscle aches
    Muscle pain can be a sign of conditions affecting your whole body, like some infections (including the flu).
  • woman holding her sore throat; cold symptoms, flu symptoms
    Sore throat
    Sore throats are most often caused by viruses so most sore throats will NOT respond to antibiotics.

The Flu Can Leave You Hot or Cold

  • sick girl lying under a blanket
    Chills
    Chills may occur at the beginning of an infection and often predict the coming of a fever, or an increase in the body's core temperature.
  • thermometer in woman's mouth for temperature
    Fever
    While a fever signals to us that a battle might be going on in the body, the fever is fighting for the person, not against.

It Might Not Be The Flu

  • woman blowing nose into tissue, common cold, flu, hay fever, allergies
    Cold Symptoms
    Sneezing, runny nose, nasal congestion, coughs and sore throat are all symptoms of the common cold. Compare your symptoms to those commonly associated with the cold.
  • Chronic cough can be an acid reflux symptom.
    Other Respiratory Illnesses
    Many infections and illnesses can cause cold symptoms or flu symptoms, but they are not cold or flu. Find out what other respiratory illnesses may be plaguing you.

All About Swine Flu

Swine Flu: The H1N1 Influenza Virus

Swine flu
Get newly updated information on the swine flu H1N1 virus and information on swine flu cases, symptoms, treatments, and vaccines.
Find out more >>

What Could Your Symptoms Mean?

Symptom Checker

Check a Symptom
Check your symptoms here to help find out if you've got the cold or the flu, allergies, or another respiratory infection.
Find out more >>