Mono vs. The Flu: Differences and Similarities

Mono and the flu share some common symptoms and similarities, but they are different. In this guide, we are going to go over the differences, causes, treatments and symptoms so that you can decipher if you are suffering with the flu or mono, and what to do about it. 

Table of Contents

What Is Mono?

Mono is the abbreviation for infectious mononucleosis. This is often what we refer to as ‘the kissing disease’ as the virus that causes mono is spread through saliva. This is why it is often referred to as a young person’s illness, affecting those between 15 and 30 years of age the most. However, mono can occur at any age. 

While mono is spread through saliva, you can catch it from sharing food utensils or glasses with someone who already has the infection, but it is not typically as contagious as a common cold or flu. 


Mononucleosis is a virus that is spread through contact with saliva from the mouth of someone already infected with mono. It can also be spread through other bodily fluids such as blood and via sexual contact. 

You can catch mono through a cough or sneeze, or by kissing someone with mono. If you share food, drinks, utensils, cups and more with someone who has the virus, you can also catch it. It will typically take around 4 weeks for the symptoms to appear after becoming infected with the virus. 

Symptoms & Signs Of Mono

Symptoms can vary from person to person, but there are some common ones to look out for if you think you may have been exposed to mono. These are:

Symptoms of mono such as a sore throat and fever typically lessen within a few weeks, whereas fatigue and swollen lymph nodes can persist for a little longer.


Most cases of mono are mild and will resolve easily after a short treatment. In many cases, mono will go away on its own within around a month. However, doctors can prescribe medications to reduce swelling of the tonsils or pain in the throat. Mono should go away with plenty of rest and fluids. 

What Is The Flu?

The flu is a contagious respiratory illness that affects the nose, throat, lungs and more. The flu is caused by an influenza virus that is spread by airborne droplets from coughs and sneezes of people who have the flu. 


The flu is highly infectious and can spread easily between people. The flu is most often spread from person to person via droplets from coughs and sneezes which can live on surfaces and pass through touching

To avoid catching and spreading the flu, you will need to cover your mouth and nose when you cough or sneeze, wash your hands well with warm water and soap, and avoid contact with other people or surfaces that may be unclean.  

Symptoms & Signs Of The Flu

Some patients will demonstrate many flu symptoms, whereas others may have only one or two of them. However, some of the common symptoms of the flu are:

  • Headaches
  • Loss of appetite
  • Sudden fever or high temperatures
  • Aches and pains in the body
  • Fatigue
  • A dry cough
  • Difficulty sleeping
  • Sore throat
  • Diarrhea and stomach pains
  • Sickness or nausea


The flu will often go away on its own after it has run its course. To get over the flu, you will need to stay warm, rest, and sleep as much as you can. Drink plenty of water to avoid becoming dehydrated, and take painkillers to lower your temperature or to treat sore throats and headaches or various other symptoms. 

Mono Vs. Flu – Differences And Similarities

Mono and the flu have many overlapping symptoms so it can be hard to decipher which is which. The easiest way to figure this out is to see when the symptoms began, how bad they are, and how long they last.

Mono is spread through saliva, and is a virus that is most contagious right before the symptoms develop, but it is not as contagious as a common cold. In addition, mono is caused by Epstein-Barr virus, or EBV, and is transmitted through bodily fluids. 

In comparison, the flu virus is a contagious respiratory illness caused by influenza viruses such as influenza A and B that can impact the lungs, nose, and throat. Flu is caused by droplets from the nose, mouth and throat. 

Flu symptoms tend to come on very suddenly and can range from mild to very severe. The flu can be more dangerous for many people due to other risk factors such as age, immunosuppressed people, or people with lung diseases. Mono symptoms tend to be mild and go away very easily. 

When it comes to symptoms, those with mono may have swollen lymph nodes, extreme fatigue and a rash. While you will get a sore throat and body aches with mono or the flu, those with the flu will suffer with a runny nose, a cough, and even vomiting and diarrhea. 

The flu can also cause complications such as dehydration, sinus and ear infections, pneumonia, and the worsening of other underlying conditions such as diabetes, COPD, asthma, heart disease, and others. On the other hand, mono can cause complications such as an enlarged spleen, liver inflammation or jaundice. 

In terms of treatment, if you have the flu or mono, you do need to rest to help your body recover, and ensure that you remain hydrated. You should also take ibuprofen to help reduce aches and pains and reduce fevers. 

However, with mono, the worst of the illness may be the throat, so you will need to gargle salt water and use lozenges to recover. You may also need to avoid sports and exercise to ensure the spleen does not rupture. 

Those with the flu may also lose their appetites, and will need to eat a lighter diet to avoid nausea, sickness and diarrhea. 

Key Takeaways

To summarize, mono and the flu do have overlapping symptoms, but they are different. With this guide, you can compare the symptoms, and consider which ailment you may have. If your symptoms worsen, then seek medical assistance to get better as soon as possible. 


Content on the DrHouse website is written by our medical content team and reviewed by qualified MDs, PhDs, NPs, and PharmDs. We follow strict content creation guidelines to ensure accurate medical information. However, this content is for informational purposes only and not a substitute for professional medical advice, diagnosis, or treatment. For more information read our medical disclaimer.

Always consult with your physician or other qualified health providers about medical concerns. Never disregard professional medical advice or delay seeking it based on what you read on this website.

If you are experiencing high fever (>103F/39.4C), shortness of breath, difficulty breathing, chest pain, heart palpitations, abnormal bruising, abnormal bleeding, extreme fatigue, dizziness, new weakness or paralysis, difficulty with speech, confusion, extreme pain in any body part, or inability to remain hydrated or keep down fluids or feel you may have any other life-threatening condition, please go to the emergency department or call 911 immediately.



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