Passing gas, especially very smelly gas, can be an embarrassing problem. Fortunately, home remedies such as diet and lifestyle changes can often prevent bad-smelling gas.

In most cases, it is natural and healthy for a person to experience intestinal gas. An average person will pass gas multiple times per day. It is not uncommon for farts to be either smelly or produce no odor at all. Both are typically considered normal.

In this article, we take a look at what can lead to smelly gas, along with the symptoms that could occur alongside. We also examine the treatment options that are available when needed.

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Smelly flatulence may be caused by high fiber in food, constipation, and bacteria.

Causes of smelly flatulence can range from harmless to potentially severe. It may not always be easy to identify what is behind smelly flatulence due to the number of potential causes.

Many reasons for smelly flatulence revolve around food or medication. However, some causes may indicate an underlying health condition.

The following are some of the more common causes of smelly flatulence:

Intolerance to food

Food intolerance is a very common cause of bad odor flatulence.

Typical conditions that can cause smelly flatulence include lactose and gluten intolerances. In both of these conditions, the body’s inability to break down lactose or gluten causes smelly gas to build up and eventually be released.

Other people may have food intolerance due to a disease such as celiac disease.

Celiac disease is an autoimmune disease that causes injuries to the digestive tract. People with celiac disease have difficulty digesting gluten, which is found in wheat products.

A person with celiac disease may also experience:

If a person suspects food allergies or intolerances, they should see a doctor to test for these conditions. This will help find the exact cause and allow the person to avoid foods that contain the offending ingredient.

Food high in fiber

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Foods high in fiber, such as broccoli, may cause flatulence to be smelly.

High-fiber foods are difficult to digest. Although very good for people’s overall health and well-being, these slow-digesting foods break down or ferment in the digestive tract. The fermentation process produces odorous gas.

In some cases, foods higher in fiber have a distinctive odor. The natural odor from these foods can also cause flatulence to be smelly.

Some foods that may cause odors include:

  • cabbage
  • broccoli
  • asparagus
  • garlic

High-fiber foods often also contain more sulfur than other types. This can cause the makeup of a person’s fart to change to include more sulfur, which has a distinct odor and will cause the person to produce smellier gas.


Certain medications can cause someone to produce smelly gas as they are digested.

One of the more common culprits is antibiotics. Antibiotics may kill off some of the healthful or “good” bacteria in the digestive tract while they work to destroy an infection.

The removal of the good bacteria causes an imbalance in the digestive tract. The imbalance can cause a person to produce bad smelling gas. This excess gas can also lead to uncomfortable bloating and constipation.


Constipation occurs when stool builds up in the colon or large intestine and cannot exit. This may be due to taking certain medications, poor diet, or other biological causes.

The buildup of stool in the colon often causes a buildup of smelly gases to occur alongside. This extra gas may cause bloating and discomfort. When finally released, the gas is often smelly.

Bacteria and infections

The digestive tract is responsible for breaking down foods into usable nutrients, which are absorbed into the blood. It also produces waste, which is passed through the colon.

The digestive tract relies on several different components to do this, including its resident good bacteria.

At times, the levels of bacteria in the digestive tract may become imbalanced, potentially leading to an infection. The infection will often cause:

  • smelly, excessive gas
  • pain in the abdomen
  • diarrhea
  • fever
  • nausea
  • vomiting
  • fatigue

When a person experiences any of these symptoms, they should consult a doctor as soon as possible.

Colon cancer

Though not as common, a person may experience excessive smelly gas due to the presence of cancer of the colon. Cancerous polyps or tumors can form blockages that cause gas to build up in the intestine.

One early warning sign is when changes in diet or medication do not stop foul-smelling gas from occurring.

After 50 years of age, a person at average risk for colon cancer should be tested to check for colon cancer.

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Changes in the diet may be a recommended treatment to reduce smelly gas.

In many cases, a person can try to treat flatulence at home. Often, changes in diet can be enough to reduce or get rid of smelly gas. These changes may require eating less of or avoiding several foods. The foods that need to be reduced or avoided will vary from person to person.

In other cases, an individual may find that medication has caused smelly flatulence. For over-the-counter medications, a person will likely find relief by stopping the product.

For prescription medications, it is advisable to speak to a doctor about alternatives if smelly flatulence becomes a problem.

A person will also want to see their doctor if:

  • they experience additional symptoms
  • changes to medication do not bring relief
  • alterations to diet do not bring improvement

In these cases, the gas may be due to an infection or underlying condition that needs treatment. A doctor can perform tests to find out exactly what is causing the gas and decide a treatment plan for the individual.

For people whose gas is caused by food intake, prevention typically involves changing their diet.

A person can try tracking food intake and times when they experience excessive, smelly flatulence. They can then eliminate or reduce the amount of the food or foods that cause excessive gas.

Some tips to avoid excessive gas include:

  • eating smaller portions
  • avoiding trigger foods
  • avoiding naturally smelly foods
  • eating slowly
  • drinking more water
  • avoiding carbonated drinks
  • including yogurt and other foods with probiotics

Some people may need to speak to a doctor about the excessive flatulence they are experiencing.

There are times when the underlying cause may be more severe than the body’s reaction to certain foods or mild constipation. In these cases, stopping the gas will often happen by treating the underlying condition.

A fart, often known as gas or flatulence, is the buildup of gases within the small intestine from digestion and respiration. It is a normal part of how the body works and often not a health concern.

In some cases, farts are silent and pass without much notice. In other cases, they can be loud and smelly. A person may experience some bloating and pressure before releasing gas.

Causes of flatulence vary. There are many foods, medications, and other factors that can affect how much and how smelly gas is in the digestive tract.

A typical fart is composed of several different gases. Most of these are not smelly. Typically, the odor is caused by variants of sulfur compounds, which are also found in some vegetables and eggs.

Exactly what gases are present depends largely on:

  • how much gas is swallowed during eating
  • the chemical reactions of bacteria and microbes in the intestine
  • what food a person has eaten

Bad flatulence is not always a cause for concern. Most people will find that bad flatulence can be managed at home with changes to their diet.

Others may need to seek out medical advice and attention if their bad flatulence does not clear up after avoiding certain foods or medications. If other symptoms also occur, it may be a sign of infection, which may need medical intervention.

Most people will experience symptom relief once the underlying cause of their flatulence is worked out and treated.