This Is What Your Excessive or Foul-Smelling Gas Could Mean

Excessive gas and unusual odors might signal digestive issues, stress or dietary problems.

If there’s one health topic that makes most people uncomfortable, it’s passing gas. But intestinal gas is completely normal and it goes unnoticed until it is passed through your mouth as a burp or your rectum as flatulence. The problem is when passing gas becomes excessive or overly foul-smelling. How can you tell if gas is just an inconvenience or a sign that something more serious is happening? 

When is gas considered “excessive”? 

“Each person has their own habits, just like they have their own facial features,” explains Bing Zhang, MD, a gastroenterologist with the USC Digestive Health Institute, part of Keck Medicine of USC. “But if you feel like you are passing more gas, feel more bloated or your gas smells different than it usually does, then that is a sign something might have changed. A significant change could signal something worth investigating.” 

What causes excessive and foul-smelling gas? 

When gas becomes excessive or particularly unpleasant smelling, it’s usually related to your diet or how your digestive system processes certain foods, Dr. Zhang says. Common dietary triggers of excessive or foul-smelling gas include: 

• Artificial sweeteners (especially sorbitol and sugar alcohols) 
• Dairy products for those with lactose intolerance 
• Fermentable carbohydrates found in beans, legumes and cruciferous vegetables 
• Gluten-containing foods (wheat, barley, rye) for those with sensitivities 
• High-sulfur foods that create odorous gas (eggs, meat, garlic, onions) 
• Simple carbohydrates like white bread and processed foods 

Dr. Zhang points out that simple carbohydrates can be particularly problematic. “Simple sugars and simple carbohydrates may increase abdominal discomfort because bacteria in your digestive system eat these up and then make gas through fermentation.” Consuming complex carbohydrates instead of simple carbohydrates can help avoid this, he says. 

While occasional gas from these foods is normal, persistent changes in gas patterns, especially when accompanied by other symptoms, might indicate underlying issues like gut bacteria imbalances, malabsorption of nutrients or inflammatory conditions. While dietary factors are often responsible for gas issues, persistent symptoms might point to underlying medical conditions. 

Medical conditions associated with gas problems 

Sometimes excessive or foul-smelling gas can be a sign of a medical problem. Dr. Zhang observes that there tends to be more gas in patients with irritable bowel syndrome (IBS), a condition often associated with anxiety and stress.  

If you experience bloating and gas specifically after consuming foods with wheat, barley or rye, it could signal celiac disease.  

For those whose symptoms appear after dairy consumption, lactose intolerance may be the culprit. According to Dr. Zhang, as you age, many lose the ability to digest lactose, resulting in gas typically within hours after consuming dairy products.  

Other conditions like small intestinal bacterial overgrowth (SIBO) or complications after bariatric surgery can also produce excessive gas. If you have had bariatric surgery, it could be that your gas is a symptom of a malfunction in the way your stomach is emptying waste into the small intestine. This condition is called dumping syndrome. It occurs when waste is rapidly flushed from the stomach into the duodenum — either too early or too late — after eating. Nausea, excessive gas, severe cramping, sweating, dizziness, diarrhea, bloating and an irregular heartbeat are some of the symptoms of dumping syndrome. 

The stress connection 

The gut-brain connection can also explain why stress and anxiety sometimes worsen gas symptoms. “The gut-brain axis is a bidirectional communication between the gut and the brain,” Dr. Zhang explains.  

Physical changes in digestion and increased awareness of normal bodily sensations can heighten anxiety. “When you feel anxious, your attention can become overly fixated on exactly how your gut feels,” Dr. Zhang says. “And the more you try not to think about the bathroom, the more you are thinking about it, creating more stress. It becomes a vicious cycle.” 

Stress-management techniques like relaxation, deep breathing, exercise or mindfulness can help break the cycle. 

How to manage excessive gas 

Taking control of gas issues starts with identifying triggers. Dr. Zhang recommends a multifaceted approach. Track your diet with a food journal to identify personal triggers and consider trying a structured approach like the low FODMAP diet if needed. Over-the-counter options such as enzyme supplements (especially for lactose intolerance) or gas-reducing medications may also provide relief. 

Simple lifestyle adjustments can also help. Eat smaller meals more slowly, limit intake of carbonated drinks and chewing gum, and stay physically active. 

When to see a doctor 

While gas itself is rarely a medical emergency, certain symptoms accompanying excessive gas warrant medical attention, including blood in the stool, changes in stool routine, unintentional weight loss, severe abdominal pain, nausea and vomiting or fever. 

“Depending on how severe your symptoms are, you should either go to the emergency room or talk to your primary doctor,” Dr. Zhang says. 

When preparing for a medical appointment about gas-related issues, keep track of when you first noticed changes, any alterations in bowel habits, and specific food triggers to help your health care provider make an accurate assessment. 

Remember that everyone experiences gas, and occasional changes in gas patterns are usually nothing to worry about. Pay attention to your baseline and be alert to significant changes that persist over time. 

Dr. Zhang reassures patients that doctors can effectively treat chronic symptoms like bloating and gas that affect quality of life. Don’t let embarrassment keep you from discussing these issues with your health care provider. Doctors are used to these conversations and can help you find relief. 

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