Home bowel disorders Why do my Farts Smell like Rotten Eggs, Sulfur or Sewage?

Why do my Farts Smell like Rotten Eggs, Sulfur or Sewage?

Do your farts smell like rotten eggs or sewage? Read on to find out why, what it means and most importantly steps to get rid of this condition.

Why does my gas smell like sulfur?

It is quite normal for you to pass gas. It is in fact normal to break the wind to as many times as 14. Gas can be passed out of the body from the gut either through the mouth through belching or burping also known as eructation or through the excretory opening by farting.

Farts Smell like Rotten Eggs Sulfur causes treatment

The characteristics of gas passed through the mouth are meant to resemble the smell of the food you have eaten such as happens after consumption of vegetables. You wouldn’t expect it to be foul but at times it is. At times you have too much gas in your gut that your burped gas smells a whole lot different.

Speaking of farting, the smell is usually horrible but you will obviously notice a difference when it is foul smelling. One such type of smell is that of sulfur. The smell of sulfur is that of a rotten egg or that produced from underneath the ground in geothermal stations. More particularly, you will talk of hydrogen sulfide gas.

 Rotten egg smell and sulfur

You must have experienced this smell even once. If you haven’t, then it is time to do a little experiment for yourself. Get an egg and store it unrefrigerated for long until it is no longer feasible. Feasibility can be measured perpetually during your experiment by performing the floating test.

If you want to reduce the time you will spend in your little experiment, then choose an egg that floats half way in water poured into a glass. This is an old egg that is probably on its way to getting rotten with a few. You could also choose one that floats completely as the best option. Break it and waft to get the smell but do not eat it. You will notice that the smell is acrid and sulfurous.

The little experiment proposed will aid in explaining the process and the science behind eggs going bad and why they smell of hydrogen sulfide. Considering the composition of eggs;

Eggs are made of globulin and keratin

Globulin is a protein just as keratin. In the process of decay, it degrades into a gas known as hydrogen sulfide. Keratin on the other hand is rich in the amino acid cysteine that is one of the few amino acids with sulfur element in its chemical structure.

Therefore, both of these proteins are responsible for the emission of hydrogen sulfide during decay. Refrigeration reduces the rate at which an egg goes rotten by stagnating the process. Oh, just to inform you, hydrogen sulfide is a flammable gas that has a higher density than air.

The decomposition process of eggs does not only involve the degradation of globulin and keratin but also change of pH. The egg yolk becomes more basic with time due to the loss of carbonic acid in the gaseous form, carbon dioxide. The reaction that leads to formation of hydrogen sulfide is catalyzed by an alkaline environment. Hence, the characteristic rotten eggs smell.

As the egg becomes more alkaline, the sulfur in the egg becomes better able to react with hydrogen to form hydrogen sulfide gas. This chemical process occurs more rapidly at room temperature than at cooler temperatures.

What do rotten egg farts mean or indicate?

It is not normal for your fart to smell like rotten egg or as you may scientifically call it, sulfur. It may mean that you have had some food with some compounds with sulfur. There are a number of foods that have sulfur in them. These include broccoli, beans and red meat. However, the smell is most eminent when you have had a lot to eat.

There are other sources that suggest the presence of enzymes that produce sulfur in the gut’s endothelium. Hence making it endogenous. This is underscored in the following section.

Causes of Gas that smells like rotten eggs and diarrhea

Endogenous hydrogen sulfide

ere is still a lot to do in providing enough evidence to back the fact that hydrogen sulfide is also an endogenous substance. The prevailing evidence suggest that there are enzymes that are in your gut responsible for its formation.

Hydrogen sulfide finds itself as a gas that is yet to find its place in your body physiologically so that it is appreciated. So far so good, cystathionine-β-synthase, cystathione-γ-lyase and 3-mercaptopyruvate sulfurtransferase (Watanabe M.O., et al 1995)[1] are the remarkable enzymes that endogenously produce hydrogen sulfide.

In fact, hydrogen sulfide is becoming a novel compound to study since the discovery of its receptors in the gut.

Halitogenic bacteria

Halitosis is mostly caused by bacteria that colonize your gut. You might burp or pass gas that is responsible for this through degradation of sulfur containing amino acid substrates. These amino acid substrates include methionine, cysteine and cystine (Harvey –Woodworth C.N., 2013)[2].

Volatile sulfur compounds such as hydrogen sulfide among others such as dimethyl sulfide, methyl mercaptan and skatole are produced when these bacteria metabolize the compounds.

It is worthwhile noting that the infamous H. pylori causes significant increase in hydrogen sulfide and dimethyl sulfide. It is not shocking that these crop of people will experience fart smelling like rotten egg.

Sulfur-containing food

There are foods that have sulfur in them. Most of proteinous foods contain some sulfur in them. When you have these foods in moderation, then it is unlikely that you will experience a rotten egg fart smell.

More considerably, onions when eaten raw could lead to s sulfurous smell. Well, at least science mentions onions whether yellow, white or red to have lots of sulfur content in them.

In fact, it is a sulfur compound that is responsible for the teary effect it has on your eyes. This lachrymatory factor is known as propanethiol-S-oxide (Prof. Dr. Michael Keusgen, University of Marburg). Garlic is not too far from this as its principal compound thiosulfinate, alliin and allicin are sulfur-based.

Gastrointestinal conditions

pylori bacterium causes peptic ulcer disease in more than 80% of people with peptic ulcer. Other conditions may include a malabsorption problem that may lead to improper binding to hydrogen sulfide produced in the gut. Binding to the hydrogen sulfide helps reduce the amount or concentration of the gas.

digestive tract infection smelly gas
Digestive tract

Why gas smells like sewage

Speaking of sewer gas, this is mostly methane. Methane is basically odorless but gets corrupted when mixed with other gases. Hydrogen sulfide is also found mixed in the sewer and this is responsible for the rotten smell. The best way to think about how a sewer could smell like is by picturing all the weird and rotten smells then mix them together.

Again, if your fart smells of sewage, then this could be a sign of decomposing gut contents. This possibility should follow your reduced bowel movements, distended abdomen and fecal impaction.

When you have a blockage due to a swelling or tumor, then it could lead to food taking too long in a compartment and this may make it smell like rotten stuff. More like a sewer.

How to get Rid of Sulfur/Rotten Egg Smelling Farts in 4 Steps

If you have a sulfur/rotten egg smell to your fart, then you need to figure out what’s wrong or not right in your gut. Here are some ways that you could use to get rid of the smell.  Some are related to lifestyle changes while others involve actual management and treatment of a condition.

Step#1: Investigating underlying conditions

it is important to visit a doctor in order to ensure that you are not infected. The doctor will be able to prescribe some drugs for you in case it is. If the smell is accompanied by other symptoms such as impaction, then further investigation will be made.

Step#2:  Dietary changes

You could make a few changes in your diet.  Some of them include:

Plenty of water

Drink lots of water. Perhaps even more than just 8 glasses in a day. Make sure that you spread out the glasses or ounces of water throughout your day, concentrated more after meals or during a time of increased physical activity.

Water is good for proper digestion and proper absorption of food. Hence, there will be little hydrogen sulfide or other compounds in the gut. It also flushes out the excessive waste and helps relieve constipation.

Green tea

This is a herbal that is known to improve digestion and detoxification process of your body. It leads to better general health inclusive of the gastrointestinal system.


There is one particular type of honey known as Manuka honey related to the tea tree and indicated for the treatment of infectious bacteria such as E. coli, Salmonella typhimurium and Staphylococcus aureus. Apart from this, it also helps in maintaining the patency of the gut walls hence aiding in the management of Irritable Bowel Syndrome (IBS)

Reduce on the intake of alcohol

Alcohol irritates the gut wall and may cause injury to them. This leads to malabsorption syndrome. It disrupts digestion in the stomach where proteins are supposed to be degraded. Hence, improper digestion leads to formation of hydrogen sulfide and then the rotten egg smell of fart and burps.

Reduce on trigger foods

The foods that lead to formation of hydrogen sulfide such as those with sulfur in them should be reduced. If garlic causes this reaction when you have it, then you need to either reduce on it or avoid it completely.

You need to identify the food that mostly leads to the smell and get an alternative. Refer to the previous sections of this material for foods that predispose you to hydrogen sulfide in the gut.

foods reduce smelly gas farts
Soft vegetables can help reduce smelly gas

Step#3: Treatment of prevailing conditions

pylori needs to be treated for its adverse effects on the stomach. This bacterium is also responsible for the formation of hydrogen sulfide and dimethyl sulfide which make your breathe or burp really bad. This bacterium is just one of the many Halitogenic bacteria that exist in our gut.

Therefore, your doctor may prescribe some medication to curb release of excess acid due to this bacterium that makes you get the ulcers but will also make sure that you get an antibiotic drug. This will help eliminate the bacterium.

If your fart smell occurs alongside diarrhea or other stomach problem, then you might be infected by other bacterium such as Salmonella spp or some E. coli. These two are commonly associated with systemic symptoms such as a fever. There are tests to identify their presence and institution of appropriate treatment made.

Step#4: Physical exercise

This piece will never underscore the importance of involving yourself in some physical exercises each day. It is known to improve your digestion.


[1] Watanabe M. Osada J. Aratani Y. Kluckman K. Reddick R. Malinow MR. Maeda N. Mice deficient in cystathionine beta-synthase: animal models for mild and severe homocyst (e) inemia. Proc Natl Acad Sci U S A. 1995; 92:1585–1589.

[2] Dimethylsulphidemia: the significance of dimethyl sulphide in extra-oral, blood borne halitosis. Harvey-Woodworth CN, Br Dent J. 2013 Apr; 214(7):E20.


  1. Why does my husband have continual burping resembling trapped wind all the time. It has been like this for months. Also he has a lot of flatulence resembling sulphur rotten egg smell.

  2. My a.s.s is pulverizing sulfur at astonishing rates. I’m thinking of sell shares of this gas. It’s only offensive to other people. I’ve learned to live with it and love myself. The first step is admitting you’re not infallible. I’m a film director and well, it took me awhile to realize that it’s ok not making Emmy awarding winning movies, or even getting nominated.


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