Stinky Poop: Causes and Solutions


Why does my poop smell so bad?

Have you ever been taken aback by the unpleasant odor of your poop? While the smell of poop is never pleasant, it can vary in intensity and odor depending on a variety of factors. In this article we will discuss why your poop smells so bad and what you can do about it.

How are gases produced that cause poop to smell?

The gases that cause poop to smell are primarily produced by the action of bacteria in the intestines. When you eat food, it passes through your digestive system, and the nutrients are broken down and absorbed into your body. The parts of the food that can’t be digested pass into the large intestine, where they are acted upon by bacteria.

These bacteria break down the undigested food using a process called fermentation, which produces gases as a byproduct. The gases produced include methane, hydrogen sulfide, and other sulfur-containing compounds, which are responsible for the strong odor of poop.

The specific types of gases produced can vary depending on the types of bacteria present in the gut and the types of food being digested. For example, foods that are high in sulfur-containing compounds, such as eggs and cruciferous vegetables like broccoli and cauliflower, can lead to the production of more hydrogen sulfide gas, which has a characteristic smell of rotten eggs.

While the gases produced by bacteria in the gut can be unpleasant, they play an important role in the digestive process. They help to break down and ferment the undigested food, and also help to keep the intestinal environment in balance. However, if you notice a persistent change in the smell of your poop, it is a good idea to speak with your gastroenterologist, as it could be a sign of an underlying digestive problem.

What causes poop to smell?

The unpleasant odor of poop is primarily caused by the presence of bacteria in the intestines. These bacteria break down the proteins and other components of digested food, producing gases such as methane and hydrogen sulfide. It is the presence of these gases that give poop its characteristic smell.

What is skatole?

Skatole, also known as 3-methylindole, is a chemical compound that is naturally present in feces (poop), as well as in other organic matter like certain plants and animal tissues. It is responsible for the distinctive odor associated with feces.

The smell of poop is a result of a combination of various compounds, including skatole. Skatole is produced during the breakdown of tryptophan, an amino acid found in various foods, by bacteria in the intestines. As these bacteria digest the food you eat, they release skatole and other volatile organic compounds. Skatole, in particular, has a very strong and unpleasant odor, often described as “fecal” or “barnyard” in nature.

Skatole and indole are some of the chemical compounds that make human poop and fart smell terribly. U.S and Israel do use skatole in crowd control sprays. When a skatole spray gets on the skin, the stench does not wash off until after 3 days.

The concentration of skatole in feces can vary depending on factors such as diet, gut health, and metabolism. A diet rich in certain foods can lead to higher skatole production, resulting in a stronger smell. Additionally, certain medical conditions or digestive issues can influence the production of skatole and other odor-causing compounds.

Indoleacetate decarboxylase (IAD) is a glycyl radical enzyme that catalyses the decarboxylation of indoleacetate to form skatole

Which foods can lead to higher skatole release in feces?

Foods that are rich in the amino acid tryptophan can contribute to higher skatole production in the intestines, potentially leading to a stronger odor in feces. Tryptophan is an essential amino acid found in various protein-rich foods. Some foods that contain tryptophan and might contribute to skatole production include:

  1. Meat: Tryptophan is commonly found in meats like beef, pork, and poultry.
  2. Dairy Products: Cheese, milk, and other dairy products contain tryptophan.
  3. Eggs: Eggs are a source of tryptophan and are commonly consumed.
  4. Fish: Fish, especially those high in protein, can contain tryptophan.
  5. Legumes: While not as rich in tryptophan as animal products, legumes like beans and lentils still contain some amount of tryptophan.
  6. Nuts and Seeds: Various nuts and seeds, including almonds, pumpkin seeds, and sunflower seeds, contain tryptophan.
  7. Soy Products: Foods made from soybeans, such as tofu and soy milk, contain tryptophan.
  8. Chocolate: Chocolate contains small amounts of tryptophan, although the overall contribution to skatole production is likely less significant compared to other sources.

What factors can affect poop odor?

  1. Diet: The types of food you eat can significantly impact the odor of your poop. For example, foods that are high in sulfur, such as eggs and cruciferous vegetables, can lead to a stronger odor.
  2. Hydration: Dehydration can make poop smell stronger, as it causes the body to reabsorb more water from the colon, leading to more concentrated waste.
  3. Medications: Certain medications can cause changes in poop odor. For example, antibiotics can alter the balance of bacteria in the gut, leading to a different smell.
  4. Digestive disorders: See below.
  5. Other health conditions: Certain health conditions, such as diabetes and liver disease, can also affect poop odor.

Which digestive problems can underlie the production of foul-smelling poop?

Several health conditions can cause the production of smelly poop. Here are some examples:

  1. Malabsorption disorders: Conditions that affect the body’s ability to absorb nutrients, such as celiac disease, lactose intolerance, and inflammatory bowel disease (IBD), can cause undigested food to pass through the digestive system, leading to the production of smelly poop.
  2. Infections: Bacterial infections in the digestive tract can cause diarrhea and produce foul-smelling poop.
  3. Gastrointestinal disorders: Conditions that affect the structure or function of the digestive system, such as irritable bowel syndrome (IBS), can cause changes in bowel movements and the production of smelly poop.
  4. Pancreatic insufficiency: The pancreas produces enzymes that are necessary for the digestion of fats and proteins. When the pancreas doesn’t produce enough enzymes, undigested food can pass through the digestive system, leading to the production of smelly poop.
  5. Liver or gallbladder disease: Diseases that affect the liver or gallbladder, such as cirrhosis and hepatitis, can cause changes in the color and smell of poop.

It is important to note that smelly poop is not always a sign of a serious health problem. However, if you notice a persistent change in the smell of your poop, it is a good idea to speak with your gastroenterologist, as it could be a sign of an underlying condition that requires medical attention.

What foods produce stinky poop?

Some foods are known to produce stinky poop. Here are some examples:

  1. Cruciferous vegetables: Vegetables like broccoli, cauliflower, and cabbage contain sulfur compounds that can cause smelly gas and poop.
  2. Red meat: Red meat is high in protein, which can produce foul-smelling gases when broken down in the intestines.
  3. Spicy foods: See below.
  4. Dairy products: Dairy products like milk, cheese, and yogurt can cause smelly poop in people who are lactose intolerant.
  5. Fried or fatty foods: Foods that are high in fat can be difficult to digest and can lead to foul-smelling poop.

Can spicy food cause foul-smelling poop?

Some spices may cause foul-smelling poop, especially when consumed in large quantities. Here are some examples:

  1. Garlic: Garlic is a commonly used spice that can cause the production of sulfur-containing gases in the intestines, leading to a strong odor in the poop.
  2. Cumin: Cumin is another spice that can cause foul-smelling poop, especially when consumed in large amounts. It can also cause digestive upset and flatulence.
  3. Curry: Curry is a blend of spices that can cause strong-smelling poop, as well as flatulence and diarrhea.
  4. Black pepper: Black pepper is a commonly used spice that can cause the production of pungent-smelling gases in the intestines.
  5. Red pepper: Red pepper, or cayenne pepper, can cause a burning sensation in the digestive tract, as well as foul-smelling poop.

It is important to note that spices are not typically a cause for concern unless they are consumed in excessive amounts or cause other digestive symptoms. If you are experiencing persistent changes in your poop, such as foul odor or diarrhea, it is a good idea to speak with your gastroenterologist, as it could be a sign of an underlying digestive problem, as mentioned earlier.

What can you do to reduce poop odor?

While it is normal for poop to have a strong odor, there are a few things you can do to help reduce the smell:

  1. Stay hydrated: Drinking plenty of water can help keep poop from smelling too strong.
  2. Eat a balanced diet: Eating a diet that is rich in fruits, vegetables, and whole grains can help keep your digestive system healthy and reduce poop odor.
  3. Take probiotics: Probiotics are beneficial bacteria that can help improve the balance of bacteria in your gut, leading to less odor.
  4. Practice good hygiene: Washing your hands thoroughly after using the bathroom can help reduce the spread of bacteria and minimize poop odor.

In conclusion, while poop odor is never pleasant, it is a normal part of the digestive process. By understanding what factors can affect poop odor and taking steps to reduce the smell, you can maintain good digestive health and minimize any unpleasant odors.

You can also have a look at another article of on the Poop Color Guide here.

You can also have a look at another article of on The Ultimate Guide of Stool Consistency here.

How can I contact gastroenterologist Dr. Zavos for an appointment?

Dr. Chris Zavos is a board-certified gastroenterologist and hepatologist, located in Thessaloniki Greece, and specifically in Kalamaria suburb, about 7 kilometres (4 miles) southeast of downtown Thessaloniki. His private office is at: Fanariou 8 street (near Aigaiou and Adrianoupoleos avenues), Kalamaria (Thessaloniki), Greece.

Thessaloniki International Airport is only 10 km away from his private office in Kalamaria and can be reached by taxi within 13 minutes from the airport.

Dr. Chris Zavos performs endoscopies at Bioclinic private hospital in downtown Thessaloniki (Mitropoleos 86 street).

You can contact Dr. Zavos at phone numbers: (+30)-6976596988 and (+30)-2311283833, or you can email him at Dr. Zavos responds to Greek and English languages.

Last update: 16 June 2024, 14:54


Gastroenterologist - Hepatologist, Thessaloniki

PhD at Medical School, Aristotle University of Thessaloniki, Greece

PGDip at Universitair Medisch Centrum Utrecht, The Netherlands

Ex President, Hellenic H. pylori & Microbiota Study Group