Why does stool smell sour and have a fermented odor?

Under normal circumstances, acidic stool with a fermented odor may be caused by various factors such as a high-fiber diet, constipation, bile reflux, indigestion, or acute gastroenteritis. It is recommended to seek medical attention promptly, identify the underlying cause, and receive appropriate symptomatic treatment under the guidance of a qualified physician. Specific analyses are as follows:

1. High-Fiber Diet

Consuming large amounts of fiber-rich foods, such as vegetables, fruits, and whole grains, may lead to acidic stool with a fermented smell. Maintain a balanced diet, consume fiber in moderation, and ensure adequate fluid intake.

2. Constipation

Chronic constipation causes stool to remain in the intestines for prolonged periods. Bacteria break down the stool through metabolic processes, producing acidic substances and gases, resulting in acidic, fermented-smelling stool. Drink plenty of water, increase dietary fiber intake, and engage in appropriate physical exercise to promote intestinal motility.

3. Bile Reflux

Bile reflux is primarily caused by dysfunction of the pyloric sphincter. When bile enters the small intestine, it may interfere with normal fat digestion and absorption. Undigested fats are then fermented by bacteria in the colon, producing acidic substances that give stool an acidic odor. Symptoms may also include upper abdominal pain and nausea. Under the guidance of a physician, medications such as mosapride citrate tablets, hydrotalcite tablets, or ursodeoxycholic acid tablets may be recommended.

4. Indigestion

Indigestion is generally associated with insufficient gastric acid secretion, leading to weakened gastrointestinal motility. Food remains in the intestines for extended periods and undergoes abnormal bacterial fermentation, producing acidic gases and substances, which results in acidic stool. Symptoms may include bloating and abdominal pain. Treatment under medical supervision may include domperidone tablets, mosapride citrate tablets, or ranitidine hydrochloride capsules.

5. Acute Gastroenteritis

Acute gastroenteritis is usually caused by bacterial or viral infections, leading to acute inflammation of the gastrointestinal mucosa, impairing digestion and absorption. Bacterial metabolism produces acidic substances and gases. Additional symptoms may include nausea and vomiting. Medications such as metoclopramide tablets, norfloxacin capsules, or atropine sulfate tablets may be taken as directed by a physician to relieve symptoms.

In daily life, maintain healthy habits, avoid spicy and irritating foods, and engage in regular physical activity.