As cold and flu season settles in, a bowl of chicken soup remains one of the most trusted home remedies around. The science behind it is thinner than its reputation, but it is not nothing. Research suggests hot soup can ease some symptoms for a short time. There is no good evidence that it cures a cold or the flu, prevents one or takes the place of medical care when it is needed.

The remedy is old. Medical writers trace it at least to Moses Maimonides, the 12th-century physician, and researchers who have studied the soup in modern times cite his writings.

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What the studies found

One of the first modern tests was a small study published in 1978 in the medical journal Chest. Researchers measured how fast mucus moved through the noses of 15 healthy volunteers before and after they drank hot water, cold water or hot chicken soup.

Five minutes after sipping hot chicken soup, mucus moved faster, from 6.9 to 9.2 millimeters per minute. Sipping hot water also sped it up, from 6.2 to 8.4 millimeters per minute. Cold water slowed it. By 30 minutes, the effects were gone, and none of the drinks changed how easily air moved through the nose.

Moving mucus is one way the nose clears out germs and debris. The researchers concluded that hot drinks help partly because people breathe in the steam, and that the soup seemed to have something extra, possibly its aroma or taste. They also suggested hot liquids may be better than cold ones for people with colds. The volunteers were not sick, however, so the study could not show whether the soup helped anyone feel better.

In 2000, researchers at the University of Nebraska Medical Center in Omaha tested a traditional homemade chicken soup in the laboratory. Many different viruses cause colds, and the researchers reasoned that the symptoms look alike because they come largely from the body's own inflammatory response.

They found the soup slowed the movement of neutrophils, white blood cells that rush to the site of an infection and drive inflammation. The more concentrated the soup, the stronger the effect. The chicken and every vegetable in the pot showed some activity on their own, and store-bought soups varied widely. The authors suggested a mild anti-inflammatory effect could be one way the soup eases symptoms.

The limits are important. The test was done on cells in a laboratory dish, not in people, and it did not show that eating a bowl of soup delivers enough of anything to make a difference in the body.

A 2008 study at the Common Cold Centre at Cardiff University in Wales came closer to real life. Researchers gave a hot fruit drink, not soup, to 30 people with colds or the flu. The hot drink brought immediate and lasting relief from a runny nose, cough, sneezing, sore throat, chills and tiredness. The same drink at room temperature helped only with a runny nose, cough and sneezing.

Measured airflow through the nose did not change, even though people said they could breathe more easily. The researchers said part of the benefit may be a placebo effect, along with the way a hot, flavorful drink increases saliva and other secretions in the mouth and airways. Their conclusion supported the folklore that "a hot tasty drink is a beneficial treatment" for most cold and flu symptoms.

The most recent look at the evidence, a 2025 systematic review in the journal Nutrients, searched for every controlled trial of soup for respiratory infections. It found just four, involving 342 people, and concluded that soup "may offer modest benefits," mostly for easing symptoms and inflammation.

Those four studies were a mixed group. One was the 1978 study of healthy volunteers. Two tested soups made with herbs or other added ingredients in patients hospitalized with COVID-19 in Iran, and the fourth tested a Chinese herbal soup in children with repeated infections. None tested ordinary chicken soup in adults with a cold. In the one trial that measured how long symptoms lasted, most of the differences were small enough that they could have been due to chance. The reviewers rated the certainty of the evidence as low to moderate and called for better trials.

What it won't do

Chicken soup does not kill viruses, and there is no evidence it keeps people from catching a cold or the flu.

"The common cold has no cure but should improve on its own," according to the Centers for Disease Control and Prevention, and colds usually last less than a week. Antibiotics do not help either. "Antibiotics don't work against viruses and won't help you feel better," the CDC says.

The flu is different, because there are medicines that treat it. According to the CDC, prescription flu antiviral drugs "work best when started within 1-2 days after flu symptoms begin" and can shorten the illness by about a day. The CDC says it is very important for people at higher risk of serious complications to start them as soon as possible. That includes people with asthma, chronic lung disease, diabetes or heart disease, people who are pregnant, and people at higher risk because of their age. Soup is no substitute.

Flu is already circulating in Colorado. Hospital admissions for the flu were running far ahead of last year's pace earlier this month, as the Kiowa County Press reported.

Why it may help anyway

The CDC recommends getting plenty of rest and drinking plenty of fluids for a cold, and a bowl of soup counts toward the fluids. It also offers warmth, steam, salt and some protein and calories at a time when many people do not feel like eating, and it tastes good. The Cardiff results suggest that the warmth and flavor themselves make people feel better, even if the cause of the illness is unchanged.

Even the standard advice to drink extra fluids has thin evidence behind it. A 2011 Cochrane review found no randomized trials testing whether it helps people with respiratory infections. It noted that some observational studies suggest pushing large amounts of fluid may cause harm in infections of the lower airways, such as pneumonia.

Many canned and boxed soups are also high in sodium, which matters for people who have been told to limit salt.

When to see a doctor

The CDC says to seek medical care for a cold if there is trouble breathing or fast breathing, dehydration, a fever that lasts longer than four days, symptoms that last more than 10 days without getting better, or symptoms such as fever or cough that improve and then return or get worse. Worsening of a chronic medical condition is also a reason to call.

For the flu, the CDC lists emergency warning signs in adults that call for care right away, including difficulty breathing or shortness of breath, persistent pain or pressure in the chest or abdomen, persistent dizziness or confusion, seizures, not urinating, severe muscle pain, and severe weakness or unsteadiness.