Smelly Gas, Causes and How to get Rid

Whether you call it farting, passing gas or breaking wind, it is a normal and physiological process. There are various ways in which you could pass gas from your digestive system. If not through belching or eructation, you could pass gas through your anal opening. Why exactly is your gas smelly and what should you do about? Read on to find out

Smelly Gas Meaning & Symptoms


A burp, eructation or belch as you may refer to it is caused by a build-up of gas in the stomach while the latter is caused by accumulation of gas in the intestines.

Like most things in life, there is always a limit to everything beyond which you say, “hey, this is not normal or this is just too much”. While gas is considered physiological, passing gas too often than is perceived normal or passing gas that is overly malodorous.

smelly gas causes and how to get rid/treat

The National Institute of Diabetes, Digestive and Kidney Diseases has offered much study and thought to this and has linked such occurrences to pre-existing medical conditions. See, stool has a characteristic smell and no one would expect you to have a fragrance to your stool. Foul-smelling feces are characterized by strong, pungent and putrid smell basically due to:

  1. Food you eat: type and quantity
  2. Drugs you have taken
  3. The bacteria present in your gut
  4. A mild or serious medical condition.

What really leads to the smell feces have on them? Here are some of the elements in stool that are responsible for the odor it emits.

  1. Nitrogen: this gas accounts for about 30-90% of the gases in the gut.
  2. Carbon dioxide: responsible for the fullness as it contributes to an increase in the gaseous volume roughly 10%. Carbon dioxide is formed due to the interaction of organic matter (food) with a hydrolytic agent such as the hydrochloric acid in the stomach. This reaction produces a salt, carbon dioxide and water.
  3. Methane: accounts for nearly 10%. This is the simplest carbon chain in an organic matter when its completely broken down. This is a flammable gas.
  4. Hydrogen: 10%. Also a flammable gas like methane.
  5. Sulfur compounds: these are responsible for gas that smells like a rotten egg or a rotten cruciferous vegetable. This is so because, sulfur builds up in the gut due to an endogenous production form enzymatic actions or from eating rotten egg.

The proportions of the gases in the fart are responsible for the severity in smell accrued.

The problem with gas is that it is a highly diverse symptom with a heck whole lot of causes that you may find difficulty underscoring. This is due to the fact that farting or passing gas is a prodrome to many medical definitions. Most of the time, you will find your doctor or yourself treating the symptom without underpinning the exact causative agent.

Another consideration is that passing gas may be a more of a problem to others than it is to you. Ever seen an individual with incessant bloating and flatulence that he or she is always complaining day in day out? Well, while it might not be a serious medical condition, passing gas has been associated with a number of disorders that are linked to the central nervous system such as anxiety.

Passing wind is never complete without a sound added to it. This process is accompanied by a variety of different noises depending on the amount of gas in the gut, the amount of effect the muscles around the lumen have on the gas and how fast the gas comes out. When the sphincter of the anal opening is a bit rigid or tight, then it may lead to increased vibrations of the air passing and hence a loud noise.

Comically, passing wind and smelly in its own sense, one that you are aware of, leads to a lot of discomfort in the perception the environment will have on you. This prompts tightening of the external anal sphincter in a bid to prevent passing wind and this leads to an inward explosion of a roar or a rumble. Again, this is equally if not more embarrassing.

All in all, a malodorous smell should be investigated and you shouldn’t take this for granted.


Passing gas is normally accompanied by signs and symptoms. You can use this to make the next step or a calculated move.

1.      Gas in higher frequencies

symptoms are not only confined to pathological processes but generally refer to subjective feelings. When gas is passed in higher frequencies than is normal, i.e. 10 times a day or 20 times, then it becomes a symptom of a condition that needs to be identified.

Malodorous gas: whether you belch or fart, if the smell is not convincing of a healthy gut, then it raises concern. Malodorous gas can be of certain characteristic smells some of which are hard to fathom.

2.      Belching/eructation/burping

it is very normal to belch after you have had a meal. When you eat, the food forces air together with it into the gut and builds up in the stomach. The air is normally accumulated in the fundus which is a small space indented into the wall of the stomach to allow for swallowed air.

When it is completely full, there is need to expel the air and this is effectively done through belching. Belching could also have a different smell, well, depending on the food you have had but also depicting infections and peptic ulcer disease or more seriously, gastroparesis.

The latter is paralysis of the gastric muscles.

3.      Bloating

This refers to a feeling of abdominal fullness with accumulation of gas in the intestines. This occurs perhaps due to hypermotility or hypomotility. There are conditions, foods and drugs that lead to an alteration of physiological intestinal motility.

4.      Abdominal distension

This is similar to bloating but relatively visible to the eye and palpation. The abdomen becomes extended outwardly indicating a blockage or excessive gas accumulation.

5.      Abdominal pain

Pain may result from distension of the luminal walls or the abdominal wall itself during distension. Discomfort therefore accompanies.

What Causes Smelly Gas/Flatulence?

Discuss the causes in relation to the following keywords

Smelly farts cancer

Cancerous and non-cancerous tumors such as polyps in the colon (colonic polyps) are a cause of gas accumulation in gut. When there is a blockage of the gut lumen, then this means that food will get trapped, decompose and lead to smelly gas within the gut.

Bacteria are also localized and lead to infections. Infections are involved with inflammations filled with pus and this can be smelly too. Cancer-associated fart does not normally occur in isolation but alongside other signs and symptoms suggestive of a more serious illness.

Such include abdominal distension, constipation and possibly a palpable mass on the abdomen.

Digestive tract infection

Infections are caused by ingestion of contaminated food or water. It can also result from an imbalance of the normal flora in the intestine. The latter could be associated with Small Intestine Bacterial Overgrowth (SIBO) in which, as the name suggests leads to an overbreeding of pathogenic bacteria.

digestive tract infection causes smelly gas
Digestive tract

Such circumstances lead to inflammations along the epithelial linings. Inflammation responding to infectious agents are usually filled with pus. Pus has white blood cells and epithelial cells that are dead. The smell of a non-hygienic would in the lumen, with limited air supply to air or dry it leads to a profoundly putrid smell.

Carbohydrate malabsorption

In fact, malabsorption is one of the most common causes of foul smelling gas. Carbohydrate is a source of methane gas when it is broken down. Bacteria in the intestines break it down further to release methane gas.

When methane gas is in excess of its normal in the stool, then your fart suffers from it too. This kind of malabsorption may be caused by loss of integrity of the intestinal wall making it failing in its absorptive mechanisms. Again, lactose intolerance is one carbohydrate that is commonly malabsorbed and this is well discussed in its own subsection below.

Lactose intolerance smelly gas

Lactose in found in milk and other dairy products. Intolerance is normally brought about by an insufficiency of Lactobacillus spp that are responsible for the digestion of lactose. Intolerance leads to inflammation due to allergic reaction to lactose content in food ingested leading to diarrhea and hypermotility. Hypermotility leads to gas.

Smelly gas at night

Farts in the night happen to be embarrassing, loud and often smelly. Nightly gas may be due to over-eating before sleep and worse off, sleeping immediately you have had your supper.

To add, at this time, you are not involved with much physical activity and therefore, motility in the gut is reduced. Food tends to stay longer in certain compartments given the low motility and the posture.

To add, the sleeping posture type also determines your digestion in the night. This is why you are informed by medical literature to have something small before you sleep since you really do not need the amount of energy provided by excessive calories.

According to Dantas RO and Aben-Athar CG (2002), during the Random Eye Movement (REM) sleep, the rate of gastric emptying is higher. However, there is reduced motility in the intestines in the night, due to loss of the migrating motor complex in the small bowel.

Then the colon decreases in tone and contractions. A supine position in sleep reduces esophageal clearance hence an increased duration of acid clearance a factor that may increase gas. It has also been shown in the same study that when in the right lateral position in sleep, reflux episodes are greater. The result is increased eructation or belching.

Very smelly stool and gas

This could be a result of an underlying condition such as a tumor blocking the lumen of the gut. There are a number of conditions associated with such a phenomenon including inflammatory bowel disease, malabsorption and gut fermentation syndrome among others.

Smelly gas during pregnancy-is smelly gas a sign of early pregnancy

Pregnancy hormones such as progesterone are linked to reduced motility of the intestines slowing digestion and in the long run causing frequent indigestion. The same hormone also relaxes the sphincter muscles of the anus making it hard to hold on against flatus.

Smelly gas after gastric bypass

Gastric bypass causes excessive flatulence and one that is smelly as a commonly unmentioned side effect. The surgery alters with your normal absorption ability. This turns into an eat-feast for bacteria that in turn produce gas.

Newborn & baby smelly gas

There is need for mothers to understand the effect of breast-milk on the gut of a baby if not properly selected. It is recommended that you forego some of the hind-milk immediately it is out by unclutching the baby once suckling has stimulated milk production.

The high fat content of hind milk could result in steatorrhea and a foul smelling gas. Other reasons would be Hirschsprung Disease, fecal impaction, gastroenteritis and constipation among others. It could also be lactose intolerance or celiac disease.

Stomach pain and smelly gas

The two are most probably caused by gastroenteritis. It is an infection of the gastrointestinal system characterized by diarrhea, stomach pain and dehydration and depending on the causative agent, a fever. Smelly gas is not uncommon.

Food-what foods give you smelly gas

Foods that can give you smelly gas include: beans (especially unsoaked), dairy products, gum, processed foods, boiled eggs and unsoaked onions. Some vegetables contain raffinose such as broccoli, asparagus and Brussels.

How to get rid of smelly Farts

Step1: Check what you eat.

Foods that actually reduce gas include:

  1. Spices such as black pepper, rosemary and basil.
  2. Chamomile tea
  3. Pawpaw
  4. Pineapple
  5. Soft vegetables
Foods that reduce smelly gas
Soft vegetables

Step 2: Try Probiotics

Probiotics are particularly good for the regulation of the imbalance of bacteria in the gut. They help in the maintenance of the physiological ration between bad and good bacteria so that the bad bacteria are always outnumbered and inhibited. Such examples include

  • Yogurt: greek yogurt
  • Kimchi
  • Kefir
  • Sauerkraut
  • Tempeh
  • Kombucha
  • Pickles

Step 3: Treatment options

The management and relief of gas can be done both according to symptomatology and by treating the underlying disease. Treatment options include:

  1. Antacids: magnesium hydroxide, sodium hydrogen carbonate, calcium carbonate, simethicone.
  2. Gripe water for colic for infants. Gripe water contains pinene which is indicated for gas.
  3. Antibiotics indicated for gastroenteritis: metronidazole, ornidazole, erythromycin, etc.
  4. Hypomotility agents: Dicycloverine, Hyoscine-S-butylbromide, mebeverine
  5. Laxative agents: indicated for constipation such as lactulose
  6. Painkillers: paracetamol, ibuprofen
  7. Activated charcoal

Note that the treatment options correlate with the cause of the gas and therefore should be chosen based on results of an investigation.

Step 4: More tips to reduce/stop smelly farts

Other tips methods you could use include:

  1. Conducting physical exercise daily to relieve gas from your bowel
  2. Drinking plenty of clean water
  3. Avoiding carbonated beverages like coke
  4. Reducing chewing of gum
  5. Eating your meal at a reasonable speed and posture.
  6. Reduce your carbohydrate intake such as corn
  7. Reducing on fast foods such as fries
  8. Avoiding gluten and lactose for those who are intolerant

How do you deal with Chronic excessive smelly gas for Weeks?

Majority of people who are suffering from smelly gas for weeks to years have shown good prognosis when they make simple dietary changes. This includes increasing the fibre content and drinking plenty of water to the tune of 2 liters per day.

This capped with daily physical exercises, avoiding foods that increase gas or make it smell bad and eating those that promote the otherwise will reduce smelly gas tremendously. If you have done this already, then it is time you visited a doctor for further investigation.


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