In January 2020, a man who would become known as the first documented COVID-19 patient in the United States arrived at an urgent care clinic.

Two of his symptoms, a cough and a fever, were among those that would become known as the telltale symptoms of COVID. But the patient had also experienced two days of nausea and vomiting.

Many of us associate COVID with respiratory issues. But some people who get sick with the virus never experience a sore throat, coughing or body aches, said Dr. Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco. Certain people end up feeling more like they have food poisoning than anything else.

That's because coronavirus is "like throwing a bomb in your body," said Ken Cadwell, a professor of medicine at the University of Pennsylvania who studies how COVID affects the gut. "You're going to feel that in multiple different organs, not just the lungs."

With COVID cases climbing, and the so-called "FLiRT" variants fueling yet another summer spread, here's how to spot, and address, the lesser-known gastrointestinal symptoms.

Recognizing and resolving stomach symptoms

In some people, gastrointestinal symptoms hit during the first few days of an infection, before they develop a fever and cough. But many people who only experience stomach symptoms "never think of it as COVID," Chin-Hong said.

Diarrhea is a common COVID-related gastrointestinal symptom, Chin-Hong said. People can also lose their appetite, and experience nausea, abdominal pain and vomiting.

COVID doesn't look the same every time you get infected, said Dr. Davey Smith, an infectious disease specialist at the University of California, San Diego. You might have cold and flu symptoms during one bout of the virus, and gastrointestinal symptoms the next time. Paxlovid, an antiviral medication that reduces the risk of severe disease, can also cause diarrhea.

Hydration is important for anyone with COVID, but drinking enough fluids is critical if you experience diarrhea or vomiting. If you're struggling to hold food down, stick to bland foods such as toast and bananas, said Dr. Adrienna Jirik, a gastroenterologist at Cleveland Clinic.

Those who share a bathroom can take steps to avoid contaminating the area with the viral particles in your waste, such as opening a window to improve ventilation.

A refresher on other COVID symptoms

The most common variants currently circulating appear to cause the same symptoms we've seen in other recent strains of the virus.

In addition to digestive discomfort, people commonly develop a sore throat, congestion or a runny nose, head and muscle aches, fever or chills, a cough and fatigue. In severe cases, they can struggle to breathe. While some people who get sick lose their sense of taste or smell, that symptom is far less common now than it was earlier in the pandemic.

Any of these symptoms can hit days after spending time with someone who has the virus. If you know you've been exposed, it's important to keep an eye out for all the symptoms, including gastrointestinal ones, Chin-Hong said.

"If everybody in your house has COVID and you have diarrhea, then you have to put two and two together," he said.