Oily Stool: 7 Common Causes (& What to Do)

Oily stools are usually a sign of intestinal changes that are interfering with the digestion or absorption of fat. This leads to fat being eliminated with bowel movements, which gives stool a yellow or white color. This condition is medically known as steatorrhea. 

Oily stool can be triggered by health conditions like Crohn's disease, cystic fibrosis, celiac disease or pancreatitis. They are usually accompanied by other symptoms like a food intolerance, abdominal pain, gas or changes in weight or appetite. 

If you notice white patches in your stool with an oily appearance, or if your stool is white or orange in color, you should see your doctor for further testing. The doctor may order a stool test, colonoscopy or food intolerance testing to identify the underlying cause and initiate appropriate treatment. 

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What causes oily stool?

Oily stool can be a sign of:

1. Celiac disease

With celiac disease, the body is unable to produce the enzyme that is responsible for breaking down gluten. In some cases, people are able to produce the enzyme, but in low, insufficient amounts. Because gluten remains undigested along the digestive tract, the immune system is stimulated, leading to lesions along the intestines. This can cause difficulty with absorption of fat and the presence of fat in the stools. 

In addition to steatorrhea, many people with celiac disease may also have abdominal bloating, loss of appetite, diarrhea and white stools. 

What to do: It is important to avoid foods that contain gluten, like bread, pasta and alcoholic drinks, to prevent symptoms. You are advised to see a registered dietitian in order to formulate a diet plan that does not lead to nutritional deficiencies. Learn more about the celiac disease diet that your doctor may recommend to help manage this condition.

2. Cystic fibrosis

Cystic fibrosis is also a cause of oily stools and happens due to genetic changes that lead to increased production of very thick, viscous secretions. These secretions can accumulate within the organs and can cause respiratory and digestive symptoms. 

In addition to oily stools, other digestive symptoms that you may notice are very large bowel movements with a strong smell, malnutrition, persistent diarrhea, constipation or difficulty gaining weight. 

What to do: You should follow your treatment plan as indicated by your doctor. Treatment may involve the use of medication that improves breathing and prevent infections. It is also important to follow a healthy diet to avoid malnutrition. Respiratory physio may also help with breathing. 

3. Crohn's disease

Crohn’s disease is a chronic change in the intestine that is characterized by inflammation of the intestinal lining. It can interfere with fat absorption, leading to oily stools, abdominal pain, diarrhea, fatigue, weight loss and loss of appetite. Learn more about what causes Crohn’s disease and how it is diagnosed. 

What to do: To relieve related symptoms, you should follow the treatment prescribed by your gastroenterologist and registered dietitian. Treatment is aimed at relieving symptoms, which can be done with medications (like steroids and antibiotics) and an easy-to-digest diet that is low in fat. 

4. Pancreatitis

Pancreatitis is another frequent cause of oily stools. When the pancreas become inflamed, the production of enzymes that breakdown and absorb fat may be affected. This can lead to fat being eliminated through bowel movements, as well as upper abdominal pain, unintentional weight loss, and bloating. 

What to do: If you suspect pancreatitis, you should see your doctor for assessment so that treatment can be initiated to reduce pancreas swelling. Patients are advised to rest, take anti-inflammatory medication, and in some cases, supplement with digestive enzymes. A light and healthy diet is advised to prevent future flare-ups of pancreatitis. 

5. Whipple disease

Whipple disease is characterized by small wounds along the intestines caused by Tropheryma whipplei bacteria. These wounds interfere with the absorption of vitamins, minerals, water and fat, which can lead to oily stools, diarrhea abdominal pain and weight loss. 

It is important for Whipple disease to be identified early on and for treatment to be initiated promptly, as this bacteria can spread to other parts of the body, including the brain.

What to do: Once this condition has been diagnosed, it is treated with antibiotics as prescribed by the doctor. Usually, ceftriaxone or penicillin are started first, followed by sulfametoxazol-trimetoprime, or doxycycline to completely eliminate the bacteria. 

6. Giardiasis

Giardiasis is an infection disease caused by Giardia lamblia parasites. It can also interfere with the digestion of fat, causing oily and yellow stools. It is also common for people with giardiasis to experience diarrhea, general malaise and abdominal bloating. 

What to do: If you notice signs or symptoms of giardiasis, you should see your doctor to order a stool test. Once confirmed, treatment with antimicrobials (e.g. metronidazole or tinidazole for 1 to 5 days) can be prescribed. 

7. After surgery 

After some gastrointestinal surgery, like removing parts of the small intestine or stomach, it is common to have a temporary change to the absorption of fat. This can lead to fatty stools. 

What to do: Oily stools after surgery are considered to be normal However, if is persists or if you also notice blood in the stools, or have fever or pain, you should follow-up with your doctor. 

How to identify fat in stools 

There are other characteristics of oily stools you can look out for, like large bowel movements that are foul smelling, shiny and float in the toilet water. You may also notice symptoms like: 

  • Extreme fatigue 
  • Excessive diarrhea or an orange color 
  • Rapid weight loss
  • Bloating and cramping 
  • Nausea and vomiting

If you present with any of these symptoms, you should see your doctor to diagnose a possible cause for the fat in the stools. Once a diagnosis is confirmed, appropriate treatment can be prescribed. 

To identify whether you have fat in your stools, you should do a stool test, which will help to quantify the amount of fat and determine a cause. To do a stool test, you should eat foods that are rich in fat for 3 days prior to testing, and on the third day, collect a sample at home. The sample should be placed in a sterile lab container and placed in the fridge until it is taken to the lab.