What is foul-smelling?
The stool typically has an unpleasant odour, but a foul-smelling stool has a solid putrid odour. Most of the time, foul-smelling stools are caused by the foods people eat and the bacteria in their colon.
However, foul-smelling stools, often loose or runny, can also present a severe health problem. They can cause diarrhoea, bloating, or gas.
The foul-smelling stool is the odour associated with stool or faeces. Stools typically have an unpleasant odour.
Stools form in the large intestine (colon) with the help of "good bacteria." Changes in odour can be due to diet or illness, such as:
- Celiac disease
- Crohn's disease
- Infections
Consult a doctor right away if you have foul-smelling stools accompanied by severe symptoms, such as severe abdominal pain, cramping, and bloody stools. See a doctor promptly if your stool odour is unusual, unexplained, persistent, or worrying.
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Get A Second OpinionCauses of foul-smelling stool and gas
Antibiotics and infection:
People taking antibiotics may experience temporary stomach pain, foul-smelling stools, and gas because the drugs disrupt the gut's bacterial balance. Symptoms typically resolve after completing antibiotic treatment and restoring healthy gut bacteria.
People who experience an overgrowth of harmful gut bacteria while taking antibiotics may notice the following signs:
- watery, foul-smelling diarrhoea, which may contain pus or blood
- pain, tenderness, and cramps in the abdomen
- fever
Lactose intolerance:
Lactose is a type of sugar found in milk and other dairy products. The human body breaks down lactose, and an enzyme called lactase digests it.
A person with lactose intolerance does not make enough lactase to digest lactose.
People who are lactose intolerant may experience the following signs after consuming dairy products:
- loose, foul-smelling stools
- bloating and gas
- abdominal cramps
- Nausea
Milk allergy:
The American College of Allergy, Asthma & Immunology (ACAAI) explains that milk allergy differs from lactose intolerance.
People allergic to milk have an immune reaction to milk and milk products.
PSigns of milk allergy include:
- bloody and foul-smelling stools
- stomach ache
- urticaria
- anaphylaxis is a rare but potentially fatal allergic reaction
Short bowel syndrome:
Short bowel syndrome (SBS) is a rare condition when part of the small or large intestine is missing or unable to function. Because of this, people with SBS often suffer from malabsorption, which can lead to severe complications. SBS can occur for many reasons. A common cause is the surgical removal of part of the intestine after treatment for inflammatory bowel disease (IBD).
Signs of SBS vary among people but can include:
- Pale, oily, and foul-smelling stools
- Severe diarrhoea
- Dehydration
- Weight and muscle loss
- Lethargy
- Malnutrition
- Bloating
- Stomach pains
Chronic pancreatitis is a persistent inflammation of the pancreas that worsens over time. It causes irreparable damage and affects a person's ability to digest food and make pancreatic hormones.
Signs may include:
- Oil, greasy, and foul-smelling stools
- Nausea
- Vomiting
- Pain in the upper abdomen and back, which gets worse with eating or drinking
- Pale or clayey stools
- Malnutrition and weight loss
Diagnosis of foul-smelling stool:
Antibiotics and infection:
In most cases, a doctor can diagnose stomach pain associated with antibiotics by doing a physical exam and asking about a person's history of antibiotic treatment. They may also request a stool sample to check for bacterial toxins.
Lactose intolerance:
People who suspect they are lactose intolerant should eliminate all dairy products from their diet for several days. After the dairy-free period, they should reintroduce milk or dairy products to see if the symptoms return.
Other diagnostic tests include:
- Blood test: This shows whether or not a person can successfully digest lactose after consuming products that contain it.
- A hydrogen breath test involves repeatedly blowing a bag after consuming lactose. If the collected air contains high levels of hydrogen, this indicates lactose intolerance.
- A stool acidity test is a test of a person's stool after ingesting lactose. A very acidic stool sample suggests lactose intolerance.
- A genetic test involves analysing a blood or saliva sample for a gene linked to lactose intolerance.
- Surgical biopsy of the intestine: A surgeon removes a small piece of the intestine for analysis.
Milk allergy:
According to the ACCAI, diagnostic tests include:
- Skin test: A doctor dabs some milk on the person's arm, then lightly pricks the area with a needle. Irritation at the site indicates an allergy.
- Blood test: This checks for antibodies to immunoglobulin E, which the body produces in response to allergens.
- Real food challenge: A person consumes a small amount of the allergen in the presence of a doctor or allergist.
Short bowel syndrome:
A doctor may order the following tests to help diagnose SBS:
- Blood tests: These can check for anaemia, malnutrition, and dehydration.
- Imaging techniques(abdominal X-rays and CT scans): These can check for obstructions and loss of bowel function.
- Liver biopsy: This can check liver function.
Chronic pancreatitis:
A doctor will do a physical exam and take a thorough medical history. They may also order the following diagnostic tests:
- CT scan
- Magnetic resonance cholangiopancreatography, a type of MRI scan that uses a dye to make it easier to see internal organs
- Abdominal ultrasound
- Endoscopic ultrasound, in which a doctor inserts a flexible tube, or endoscope, into the small intestine through your mouth
Treatment for foul-smelling stool
Antibiotics and infection:
Usually, symptoms of foul smelling go away soon after a person finishes antibiotic treatment. In the meantime, the following home treatments may help reduce the severity of symptoms:
- Drink lots of fluids.
- Avoiding wheat, dairy, and foods high in fibre, which can further irritate the intestines
Milk allergy:
- The only way to manage a milk allergy is to avoid milk and products containing milk.
- The ACCAI also notes that a doctor or allergist may advise someone with a milk allergy to carry an epinephrine pen.
- These allow a person to self-inject epinephrine in the event of anaphylactic shock.
Short bowel syndrome:
Doctors usually tailor treatment for SBS to a person's symptoms and the amount of bowel they affect. Some treatment options include:
- Anti-diarrheal drugs
- Medicines to replace the intestinal lining
- Dietary adjustments
- Intravenous fluids
- Surgery
Chronic pancreatitis:
According to the National Pancreas Foundation, treatments for chronic pancreatitis focus on pain relief. They may include:
- Take pain relievers
Undergoing a Whipple procedure or surgery to remove pancreatic lesions, having a pancreatectomy or surgery to remove all or part of the pancreas
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Book an AppointmentWhen to see a Doctor?
Visit to Gastroenterologist if you experience any of these:
- Black or pale stools often
- Blood in the stool
- Changes in the stool related to diet
- Chills
- Cramping
- Fever
- Pain in the abdomen
- Weight loss
How to prevent foul-smelling stool?
Here are some ways to prevent foul-smelling stools:
Make dietary changes:
Dietary changes can help prevent foul-smelling stools. For example, avoid drinking raw or unpasteurized milk. If you have a condition that affects how you absorb food or how your body responds to certain foods, your doctor can create the proper diet for you.
Following this diet plan can help reduce symptoms such as:
- Abdominal pain
- Abdominal bloating
- Foul-smelling stool
For inflammatory bowel disease (IBD), you can follow a diet low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs).
Handle food correctly:
Avoid bacterial infections in your food by handling it properly. Cook raw foods well before eating them. Examples include:
- Beef
- Poultry
- Pork
- Eggs
- Cooking well means checking the internal temperature of your food with a thermometer before you eat it.
- Check with your local health department for the minimum internal temperature each type of food should reach before eating it.
- Do not prepare meat and vegetables on the same cutting board. Preparing them on the same board can spread Salmonella or other bacteria.
- You should also wash your hands thoroughly after handling raw meat or using the toilet.
