Diarrhea when sick with a cold happens because viral infections often irritate the digestive tract, triggering loose stools. While not all colds cause diarrhea, respiratory viruses like rhinovirus or coronavirus can spread to the gut, leading to inflammation and fluid loss.
When you have a cold, your immune system fights the virus by releasing inflammatory molecules called cytokines. These can disrupt normal digestion, speeding up food movement through the intestines and causing diarrhea. The same viruses that infect your nose and throat may also invade gut cells, worsening symptoms.
Cold-related diarrhea usually falls into two categories:
A study published in Clinical Infectious Diseases found that up to 20% of people with viral respiratory infections develop gastrointestinal symptoms, including diarrhea.
Many assume diarrhea only comes from stomach bugs, but viral respiratory infections can also cause it. Unlike bacterial infections, viral diarrhea typically resolves within a few days as your immune system clears the virus.
To manage diarrhea when sick with a cold, focus on hydration and gentle foods. Drink electrolyte solutions, avoid dairy and fatty foods, and stick to the BRAT diet (bananas, rice, applesauce, toast). Over-the-counter antidiarrheals like loperamide can help, but check with a doctor first if symptoms persist.