Skip to Content

Why is my poop highlighter yellow?

Seeing an abnormal stool color can be alarming. Highlighter yellow poop is not normal and may indicate an underlying issue. In this article, we’ll explore the common causes of yellow stool and when you should see a doctor.

What Causes Yellow Stool?

There are a few potential causes of yellow stool:

  • Diet – Eating large amounts of carrot, pumpkin, sweet potatoes, turmeric, or yellow food coloring can turn stool yellow.
  • Medications – Taking multivitamins or antibiotics like amoxicillin can cause yellow stool.
  • Digestive conditions – Issues like gastroenteritis, giardiasis, and celiac disease can lead to fatty yellow stool.
  • Liver or pancreatic conditions – Jaundice, hepatitis, cirrhosis, or pancreatic cancer may cause yellow stool.

Let’s explore these causes in more detail.

Dietary Causes

In many cases, yellow stool is caused by your diet. Here are some common culprits:

Carrots, Sweet Potatoes, Turmeric, and Pumpkin

Eating large amounts of yellow or orange foods like carrots, sweet potatoes, turmeric, and pumpkin can impart a yellow hue to your stool. These foods are high in beta-carotene, which gets digested and absorbed in the small intestine. The remaining carotenoids pass into the large intestine and color the stool yellow.

This stool color change is harmless. Your body is simply passing the excess pigments. The yellow color should go away once you stop eating so many colored foods.

Yellow Food Coloring

Artificial yellow food coloring like tartrazine or sunset yellow can also cause yellow stool. Foods like cereals, candies, and even some brands of macaroni and cheese contain these additives.

As with carotenoids, the excess food coloring gets excreted in stool. The color change is temporary and reverses after stopping the offending foods.

Medication Causes

Certain medications can also lead to yellow stool. Here are two examples:


Iron supplements or multivitamins, especially those containing vitamin C, can cause yellow-green stool. The b vitamins riboflavin and folic acid can also contribute to this color change.

Unlike food-related culprits, stool color changes from vitamins only occur at very high doses. If you see yellow stool and regularly take vitamins, consider switching brands or lowering your dosage.


Antibiotics like amoxicillin, cephalosporins, and augmentin are frequent offenders. Between 3-10% of people taking these medications will develop yellow diarrhea.

Antibiotics can cause yellow stool by altering gut flora, resulting in excess fat in stool. They may also increase intestinal cell sloughing. The antibiotic itself or its metabolites may also get excreted in stool.

This side effect isn’t cause for concern. However, if you develop severe diarrhea after starting antibiotics, call your doctor.

Digestive Condition Causes

Yellow stool can also signal issues with digestion and nutrient absorption. Here are some possibilities:


Gastroenteritis refers to inflammation of the GI tract, usually due to an infection. The most common cause is norovirus. Symptoms include diarrhea, vomiting, cramping, and fever.

Diarrhea may start out yellow and become more watery. This occurs as the body clears out digested and undigested fat in the small intestine. Once the fat is gone, stools become looser and lighter.

Most cases of gastroenteritis resolve within a few days without treatment. Drink plenty of fluids and call your doctor if symptoms persist.


Giardiasis is caused by a microscopic parasite called Giardia lamblia. Symptoms include foul-smelling yellow diarrhea, gas, bloating, fatigue and weight loss.

Giardia disrupts the small intestine’s ability to absorb fat. This leads to excess fat in stool, causing the yellow color.

Antibiotic medication like metronidazole or tinidazole is used to treat giardiasis. See your doctor if you suspect this infection.

Celiac Disease

Celiac disease is an autoimmune disorder triggered by gluten. Eating gluten causes inflammation and damage to the small intestine.

Common symptoms are diarrhea, abdominal pain, fatigue and unintended weight loss. Stools often become fatty and foul-smelling.

A gluten-free diet is the only treatment for celiac disease. Strict avoidance of gluten helps the gut heal. See your doctor if you suspect celiac disease.

Liver and Pancreas Related Causes

Finally, serious conditions affecting the liver or pancreas can also lead to yellow stool. These include:


Hepatitis refers to inflammation of the liver, often caused by a viral infection. The hepatitis A, B and C viruses attack liver cells and cause tissue damage.

In addition to yellow eyes and skin, hepatitis can cause clay-colored stool as the flow of bile gets disrupted. Other symptoms include fever, fatigue, nausea, and abdominal pain.

Hepatitis A usually resolves on its own, while hepatitis B and C can become chronic infections. See your doctor immediately if you suspect hepatitis.


Cirrhosis occurs when liver injury leads to permanent scarring and liver dysfunction. Causes include chronic hepatitis, alcohol abuse and fatty liver disease.

As cirrhosis progresses, the liver loses its ability to properly excrete bile. This leads to yellowed skin and eyes, dark urine and pale yellow stool.

Treatment involves stopping the cause of damage and managing complications. See your doctor if you notice yellowing of the skin or eyes.

Pancreatic Cancer

A tumor on the pancreas can obstruct bile flow and cause excess fat in stool, appearing yellow. Pancreatic cancer also causes symptoms like mid-back pain, unexplained weight loss, and oily stool.

Unfortunately, pancreatic cancer is difficult to detect early and has a poor prognosis. Seek evaluation if you have any troubling digestive or abdominal symptoms.

When to See a Doctor

Yellow stool due to diet or medication use isn’t necessarily cause for concern. However, schedule an appointment if you experience:

  • Prolonged yellow stool beyond 3-4 days
  • Severe or bloody diarrhea
  • Fever, vomiting, or abdominal pain
  • Unexplained weight loss
  • Yellowing eyes or skin

These symptoms could indicate an underlying infection, absorption problem, or liver issue needing evaluation.

Diagnosing Yellow Stool

To diagnose yellow stool, your doctor will ask about your symptoms and medical history. Be prepared to describe:

  • Color changes – When did it start? How long has it lasted?
  • Diet – Any new foods, supplements, or artificial coloring?
  • Medications – Both prescription and over-the-counter
  • Bowel habits – Constipation, diarrhea, changes in consistency?
  • Other symptoms – Pain, nausea, vomiting, fever?

Your doctor will likely perform a physical exam focusing on the abdomen. They may feel for areas of tenderness or organ enlargement.

If the cause isn’t clear, the following tests may be recommended:

  • Stool sample – Checking for blood, parasites, or fat content
  • Blood tests – Complete blood count, liver enzymes, bilirubin
  • Imaging – Ultrasound, CT, or MRI scan of the abdomen
  • Endoscopy – Camera images of the upper or lower GI tract

Most cases of yellow stool resolve on their own or have an easily treatable cause. But significant or persisting color changes deserve follow up to rule out underlying illness.

Treatment for Yellow Stool

Treatment depends on the underlying cause of yellow stool:

Dietary Changes

Eliminating suspect foods, artificial coloring, or high-dose vitamins often stops diet-related yellow stool. Increase fiber to promote regular bowel movements.

Medication Changes

Switching antibiotics or lowering vitamin doses can help if medications are the culprit. Always consult your doctor before stopping prescribed meds.

Treating Infections

Gastroenteritis usually resolves on its own with rest and hydration. Giardiasis requires prescription antibiotics to kill the parasite.

Gluten-Free Diet

Following a strict gluten-free diet helps manage celiac disease. Significant improvement usually occurs within weeks to months.

Liver Disease Management

Treating hepatitis involves antiviral meds and avoiding alcohol. Cirrhosis treatment focuses on the underlying cause and preventing complications.

Pancreatic Cancer Treatment

Treatment options for pancreatic cancer include surgery, radiation, chemotherapy, and targeted drug therapy. Early intervention provides the best chances for remission.

Home Remedies for Yellow Stool

For temporary yellow stool caused by diet or supplements, try these home remedies:

  • Increase hydration – Drink more non-caffeinated fluids
  • Eat high-fiber foods – Fruits, veggies, beans, whole grains
  • Take probiotics – Yogurt, kefir, fermented foods
  • Limit fatty foods – Greasy, fried, and processed foods

Improving fluid intake, fiber, and gut bacteria may help normalize stool. Limiting fat also minimizes excess in stool until color normalizes.

Preventing Yellow Stool

You can take these steps to prevent temporary yellow stool:

  • Limit colored foods – Carrots, sweet potatoes, yellow cake icing, food dyes
  • Read ingredient labels – Watch for artificial food coloring
  • Reduce vitamin C and iron supplements – Unless recommended by your doctor
  • Finish antibiotic course – Don’t stop mid-treatment unless directed

Being mindful of dietary and medication sources of yellow stool can prevent recurrence. But always finish prescribed antibiotic courses to prevent resistance.

When to See a Doctor

Schedule an urgent visit if yellow stool persists over 3-4 days or you have these symptoms:

  • Severe cramping or diarrhea
  • Blood or mucus in stool
  • Fever over 101 F (38.3 C)
  • Unintentional weight loss
  • Fatigue or muscle weakness
  • Yellowing of skin or eyes

These signs could indicate a serious medical issue needing evaluation. Seek emergency care for:

  • Difficulty breathing or swallowing
  • Chest pain
  • Uncontrolled vomiting
  • High fever
  • Confusion or fainting

If you are experiencing any concerning symptoms along with yellow stool, don’t hesitate to be seen. Call 911 or go to the ER if you have a medical emergency.


  • Diet, supplements, antibiotics, and digestive conditions can cause yellow stool.
  • See your doctor if it persists over 3-4 days or you have concerning symptoms.
  • Treatment focuses on the underlying cause, which may require diet changes, rehydration, probiotics, or prescription medication.
  • Seeking timely treatment is important, as yellow stool can occasionally indicate a serious medical problem.

Yellow stool is usually temporary and harmless. But it’s always a good idea to discuss significant or persistent changes in bowel habits with your doctor. They can help determine if anything serious is going on.