Flu Symptoms

Medically Reviewed by Nayana Ambardekar, MD on December 17, 2019

Common Flu Symptoms

Unlike cold symptoms, signs of the flu tend to come on suddenly. You might have:

Adults with seasonal flu don’t usually have stomach problems like vomiting or diarrhea, but children sometimes do.

Get medical help right away if you have:

  • Trouble breathing or shortness of breath
  • Pain or pressure in your chest or belly
  • Sudden dizziness
  • Confusion
  • Severe vomiting

These symptoms can mean your illness is severe.

Flu Symptoms vs. Cold Symptoms

The symptoms of colds and flu can be a lot alike. Here’s how to tell which one is making you sick:

  • Fever. It can last 3 or 4 days with the flu; it’s rare with a cold.
  • Aches. They might be severe with the flu; they’re mild with a cold.
  • Chills. You’re likely to have them with the flu, but they’re rare with a cold.
  • Fatigue. This is common with the flu and happens sometimes with a cold.
  • Sneezing. You’re more likely to have this with a cold than with the flu.
  • Cough and chest discomfort. This is common with both but tends to be severe with the flu.
  • Stuffy nose. This sometimes happens with the flu but is common with a cold.
  • Sore throat. This can be common with the flu but is more likely with a cold.
  • Headache. This is common when you have the flu but rare with a cold.

How to Treat Flu Symptoms

In most cases, the best things to do when you have the flu are:

  • Rest at home.
  • Drink plenty of fluids.
  • Avoid contact with other people.

Your doctor might give you prescription medications called antiviral drugs if you’re at higher risk of complications, such as if you:

These medicines -- baloxavir marboxil (Xofluza), oseltamivir (Tamiflu), peramivir (Rapivab), and zanamivir (Relenza) -- work best when you take them 48 hours or less after your symptoms start. If you take them during this window, they can cut your illness short by a day. They can also help after 48 hours if your illness is severe.

Flu Complications

People who are otherwise healthy don’t usually have serious problems from the flu.

Flu complications include:


When Is Flu Season?

Seasonal flu follows a pattern, starting in the fall and ending in the spring. The first sign is often a sudden rise in the number of school-age children sick at home. This is soon followed by more illness in other groups, including parents.

WebMD Medical Reference



CDC: "Key facts about seasonal influenza (flu)," "Questions and Answers: Swine Flu and You," "Key Facts about Swine Influenza (Swine Flu)." “What You Should Know about Antiviral Drugs,” “The Flu: What To Do If You Get Sick,” “Flu Symptoms & Complications.”

National Institute of Allergy and Infectious Diseases: "Flu (Influenza): Symptoms."

National Jewish Medical and Research Center: "Influenza and the Flu Vaccine."

Asthma and Allergy Foundation of America: "Flu (Influenza)."

American Lung Association: "Influenza Fact Sheet," “Influenza (Flu).”

Mayo Clinic: “Influenza (flu).”

Merck Manual Consumer Version: “Influenza (Flu).”

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