The common cold is a respiratory condition that causes similar symptoms to the flu. It usually starts with a runny nose followed by a sore throat and fatigue. A 2019 research review showed that symptoms normally resolve within 3 days and rarely last more than 5 to 7 days.

Diarrhea is a condition that causes loose, watery stools and the frequent need to have a bowel movement. Some viruses that cause the cold can also cause diarrhea.

It’s not uncommon to experience cold symptoms and diarrhea together. But diarrhea is more typically a symptom of the flu than a cold.

Let’s take a deeper look at the connection between diarrhea and the common cold. We’ll also take a look at other conditions that might cause diarrhea and cold-like symptoms together.

Diarrhea isn’t among the most common symptoms of a cold, but it can be a symptom in some cases.

More typical cold symptoms are:

Many types of viruses can cause a cold, but viruses in the rhinovirus family are the most common culprits. Some forms of coronavirus, human parainfluenza virus, adenovirus, and respiratory syncytial virus can also lead to the common cold.

According to the Centers for Disease Control and Prevention (CDC), viruses in the adenovirus family can cause inflammation of your stomach or intestines that leads to:

  • diarrhea
  • vomiting
  • nausea
  • stomach pain

Having a cold may also indirectly lead to diarrhea if you’re taking cold medications that upset your digestive system.

Can a cold cause diarrhea in toddlers and babies?

According to a 2016 research review, rotavirus infections are the most common viral causes of diarrhea and vomiting in children. The rotavirus doesn’t fall into the category of viruses considered cold viruses. In children and adults, a rotavirus infection is often referred to as the stomach flu.

The adenovirus and rhinovirus are two types of cold viruses that can potentially cause diarrhea in children.

The same research review above showed that adenoviruses are responsible for about 1.5 to 5.4 percent of diarrhea cases in children under 2 years old.

In a 2016 study, researchers examined the symptoms of respiratory infections in a group of 993 children under 2 years old. The researchers found that in 9.6 percent of cases, vomiting or diarrhea were the symptoms of children that developed the rhinovirus infection.

Diarrhea can’t directly cause a cold, but it may weaken your immune system and make you more prone to infection.

According to a 2017 research review, it’s estimated that about 70 percent of all the lymphocytes in your body are in your digestive tract. Lymphocytes are specialized white blood cells that help you fight infections.

A 2016 research review showed that your digestive system also hosts more than 1,000 types of bacteria. Many of these bacteria play an important role in your body’s immune system.

Having diarrhea may potentially disrupt levels of bacteria in your gut and put you at risk of developing infections.

Diarrhea can be caused by the following infection types:

  • viral
  • parasitic
  • bacterial

Other potential causes of diarrhea include food intolerances or intestinal conditions.

If you’re experiencing diarrhea together with cold symptoms, it could also be a symptom that you have one of the following.

Flu

The flu can cause many of the same symptoms as a cold such as coughing, a runny nose, and sore throat. It’s not uncommon for the flu to also cause:

  • diarrhea
  • vomiting
  • nausea

According to the CDC, diarrhea is a more common flu symptom in children than adults.

COVID-19

Some people with COVID-19 don’t experience any symptoms while other people need emergency medical care.

Symptoms of COVID-19 vary among people, but many people have flu-like symptoms, such as:

  • fever
  • cough
  • fatigue

Diarrhea and other vomiting are also relatively common COVID-19 symptoms.

Food poisoning

Food poisoning commonly causes gastric symptoms such as vomiting or diarrhea. Your body’s immune response can lead to general cold-like symptoms, such as:

Stomach flu

Viral gastroenteritis, otherwise known as the stomach flu, can be caused by a number of different types of viruses. Common symptoms include:

Hay fever

Hay fever is an allergic reaction to allergens like:

  • pollen
  • mold
  • dander

Hay fever commonly causes cold-like symptoms, such as:

  • runny nose
  • tiredness
  • coughing
  • sneezing

A small 2014 study showed that some people with pollen allergies may also experience digestive disturbances like diarrhea or vomiting.

The best way to treat diarrhea caused by a cold or the flu is often with plenty of rest. Diarrhea can lead to dehydration, so it’s also important to drink plenty of fluids and to replenish lost electrolytes. A few sources of electrolytes that are easy to digest include:

  • soup broths
  • sports drinks
  • prepackaged electrolyte mixes

COVID-19

If you only have mild symptoms, you can treat COVID-19 the same way you would treat the flu while taking extra care to avoid contact with others. If you have severe symptoms, you should contact a medical professional right away.

Medical emergency

Go to the ER or call 911 and tell the dispatcher you believe you may have COVID-19 if you have the following symptoms:

  • trouble breathing
  • persistent pain in your chest
  • new confusion
  • an inability to wake
  • bluish lips or face

Food poisoning or stomach flu

You can usually treat food poisoning or the stomach flu at home. Along with rest, it’s important to drink plenty of fluids and replace your electrolytes.

Some over-the-counter (OTC) medications like Pepto-Bismol may help you manage symptoms, but you should talk with a doctor before taking it since these medicines may suppress your body’s ability to get rid of the virus. It’s a good idea to avoid:

  • caffeine
  • alcohol
  • nicotine
  • foods that irritate your stomach

Hay fever

Treatment for hay fever starts by avoiding allergens as much as possible. OTC antihistamines are also often helpful for relieving allergy symptoms. If you have severe symptoms you may need prescription medication.

Most of the time, calling a doctor isn’t necessary when dealing with a cold or diarrhea.

For adults, it’s a good idea to seek medical attention if your diarrhea doesn’t resolve after 2 days or if you have severe pain. For children, it’s a good idea to schedule an appointment with a doctor if symptoms don’t resolve after 24 hours.

If your cold symptoms haven’t gotten better after about 10 days or if you have any unusual or severe symptoms, it’s a good idea to call a doctor.

Diarrhea isn’t among the most common symptoms of a cold, but it can be a symptom of some cold viruses. Diarrhea is more typically a symptom of the flu or a stomach bug.

If you’re dealing with a cold, it will usually go away within a week. If your symptoms haven’t resolved after 10 days, you may want to call a doctor.