During the hot season, many people may notice that they or those around them experience diarrhea or loose stools more frequently than usual, whether it is watery stools, abdominal cramps, nausea, or unusually frequent bowel movements. Although these symptoms often seem like minor health issues that resolve on their own, in reality, summer diarrhea is related to multiple factors including food, pathogens, and environmental changes directly affecting the gastrointestinal system.
Understanding why the hot season increases the risk of diarrhea helps us prevent and properly care for gut health.
The gastrointestinal system plays an important role in digestion, nutrient absorption, and regulating the body's water balance. When abnormalities occur, such as infection, intestinal irritation, or exposure to contaminants, the system responds by increasing intestinal motility and reducing water absorption, resulting in loose stools or diarrhea. In summer, various factors can easily trigger this process.
1. High temperatures promote rapid growth of pathogens. High temperatures during summer provide an ideal environment for bacteria and microbes in food, such as Salmonella,Escherichia coliand Vibrio. If food is improperly stored, for example left at room temperature too long, contamination can occur easily. Consuming such food can cause food poisoning and intestinal inflammation, leading to diarrhea.
2. Food spoils more quickly than usual In summer, especially cooked food, meat, seafood, or dishes containing coconut milk can spoil faster if kept in high temperatures. Although the food may appear normal, bacteria may already be multiplying, causing symptoms such as abdominal pain, nausea, vomiting, and acute diarrhea.
3. Unclean water and ice Cold beverages are popular in summer, but if drinking water or ice is not properly processed, it may be contaminated with pathogens. Some bacteria, intestinal viruses, and certain parasites can survive in water and enter the body through consumption.
4. Summer eating habits that stimulate the intestines Summer often changes eating patterns, such as more frequent dining out, eating street food, drinking cold or very sweet beverages, and consuming spicy or heavily seasoned foods. These can stimulate intestinal activity, causing loose stools in some people, especially those with sensitive digestive systems.
5. Dehydration affects gut balance Hot weather causes increased water loss through sweating. Inadequate fluid intake can alter the gut microbiome balance and disrupt gastrointestinal function. Some may experience bloating, cramps, and intermittent diarrhea.
Although most diarrhea improves within 1–2 days, you should see a doctor for further diagnosis if you experience:
Especially children, the elderly, or those with chronic illnesses should be evaluated by a doctor to prevent dehydration and complications.
Proper care of the gastrointestinal system can reduce diarrhea risk by recommending:
Diarrhea in summer is often caused by contamination of food and water, as well as changes in eating habits during hot weather, which can irritate or inflame the gastrointestinal tract. Although most cases improve quickly, if there are multiple daily loose stools, high fever, severe pain, excessive vomiting, or symptoms lasting more than 2–3 days, medical consultation is advised for proper diagnosis and treatment. Especially for children, the elderly, or those with chronic conditions, diarrhea can easily lead to dehydration and complications. Consulting a gastroenterology specialist helps assess causes, plan treatment, and prevent long-term health issues.
Information provided by Dr. Choti Luengchorsiri, Director of the Center of Excellence for Gastrointestinal and Liver Endoscopy, Phyathai 2 Hospital