Oily stool, also known as steatorrhea, occurs when the intestines cannot properly digest or absorb fat, causing it to be eliminated in the stool. This gives bowel movements a greasy, pale, or yellow appearance and may indicate an underlying digestive problem.
Oily stool is often linked to conditions such as Crohn’s disease, celiac disease, cystic fibrosis, pancreatitis, or infections like giardiasis. These issues can interfere with the breakdown of nutrients and lead to symptoms like bloating, abdominal pain, diarrhea, or changes in weight and appetite.
Depending on the cause, treatment may include dietary changes, enzyme supplements, antibiotics, or medications to reduce inflammation. Identifying the cause through stool tests or other diagnostic exams is essential to restore proper digestion and prevent complications.
Main causes
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. When gluten isn’t properly digested, it triggers an immune response that damages the lining of the small intestine. This injury interferes with fat absorption, leading to fatty 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 helps prevent infections. It is also important to follow a healthy diet to avoid malnutrition. Respiratory physical therapy 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 break down 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 medications, 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 trimethoprim/sulfamethoxazole 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 it 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
Characteristics of oily stools to look out for include 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 orange-colored stool (poop);
- Rapid weight loss;
- Bloating and cramping;
- Nausea and vomiting.
If you notice any of these symptoms, consult your doctor to determine the cause of fat in your 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.