COVID-19 is primarily known for its respiratory symptoms, but it can also affect the digestive system, leading to various gastrointestinal issues. While green stool might seem unusual, changes in stool color and consistency can occur during an infection, including with COVID-19. This article explores the potential digestive impacts of the virus and the general mechanisms behind stool color changes.
COVID-19 and Digestive Manifestations
COVID-19 can significantly impact the gastrointestinal (GI) system, with about 50% of infected individuals experiencing digestive symptoms. These can include diarrhea, nausea, vomiting, and abdominal pain. For some, these GI issues may be the initial or sole indicators of infection, appearing before or without respiratory symptoms like cough or fever.
The virus affects the GI tract because SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) receptors, which are abundant on the epithelial cells lining the intestines. This direct infection can lead to inflammation and disrupt the normal balance of gut microbes. Diarrhea is a common GI symptom, reported in 10% to 49.5% of COVID-19 patients, typically involving loose, watery, and non-bloody stools lasting 2 to 6 days. Abdominal pain, while less common than diarrhea or nausea, can also occur due to inflammation in the intestines.
Understanding Green Stool
Stool color is typically brown due to the breakdown of bile pigments as they pass through the digestive tract. Bile, a yellowish-green fluid produced by the liver and stored in the gallbladder, changes color from green to yellow and then to brown as bacteria act on its pigments in the intestines.
Green stool can occur when food and bile move through the intestines too quickly, a process known as rapid transit. When transit is fast, bile pigments don’t have enough time to be fully broken down by bacteria, retaining their greenish hue. Rapid transit can be caused by factors like infections such as gastroenteritis, which speed up the digestive process. Certain foods rich in chlorophyll (e.g., leafy green vegetables like kale, spinach, broccoli), or foods with green, blue, or purple food dyes, can contribute to green stool. Additionally, some medications, such as antibiotics, laxatives, or iron supplements, can lead to green stool by altering gut bacteria or speeding up digestion.
When to Consult a Doctor
While occasional green stool is often not a cause for concern and can be linked to diet or minor digestive upset, certain accompanying symptoms warrant medical attention. If green stool is persistent or occurs with other concerning signs, it is advisable to consult a healthcare professional.
Symptoms that should prompt a doctor’s visit include severe abdominal pain or cramping, persistent diarrhea lasting more than three days, signs of dehydration (such as dark urine or dizziness), fever, or unexplained weight loss. The presence of blood in the stool, which can appear bright red or black and tarry, also requires immediate medical evaluation. These symptoms could indicate an underlying condition requiring diagnosis and treatment beyond a typical viral infection.