Why Your Poop Smells Metallic: Causes & How to Fix

Key takeaways:

• Metallic-smelling poop is often a sign that you have high amounts of iron in your body.
• High iron content (which ends up in your poop) may be caused by iron in your diet, medications, iron supplements, or vitamins with iron.
• Metallic-smelling poop may also be a sign that you have blood in your stool, which can be caused by an ulcer, stomach irritation, infection, or possibly cancer.

A bowel movement that smells like metal will undoubtedly cause some alarm bells to ring. There could be simple reasons for it, however, so it’s important to understand when to be concerned.

This article will discuss the possible causes of metallic-smelling poop (also called stool), simple treatments or home remedies, and when to see a doctor.

What is metallic-smelling poop?

The texture, color, and smell of your poop may change based on your diet, medications, supplements, or gastrointestinal (GI) illnesses.

The body normally uses several important trace elements (or metals), which are part of many different foods. These elements include iron, copper, and zinc, among others. Iron is a special element the body uses in your blood cells to help carry oxygen. When there’s iron in your poop, it can have a metallic smell.

Is it normal for your poop to smell metallic?

While your poop shouldn’t usually smell metallic, it doesn’t mean there is something to be concerned about.

When you eat food, your intestines absorb nutrients. The first part of your small intestine (known as the duodenum) absorbs iron. If there’s an issue with absorbing these nutrients, or bleeding from an ulcer or stomach irritation, you may notice a metallic smell from iron buildup in your stool.

Causes of poop that smells metallic

You can have high iron levels in your stool for many reasons. It may be related to eating foods that are high in iron, taking too many iron supplements, poor absorption of iron by your intestines, or blood in your stool.

This section will discuss the possible causes of high iron in your stool and when to be concerned.

Iron from your diet

Diets high in iron are one possible cause of having poop with very high iron levels. Iron is found in red meat; seafood; dark green, leafy vegetables; and fortified grains (bread, cereals).

Iron in meat is typically well absorbed by your body, whereas plant-based iron is not. Eating a high-iron diet may also irritate the lining of the stomach or cause ulcers, which could lead to bleeding. This combination may ultimately cause you to have metallic-smelling poop.

Medications, supplements, or vitamins

Medications, supplements, or vitamins can also cause high iron levels in your poop. All these may affect how your intestines absorb nutrients, which can cause lower iron absorption in your intestines.

If you take supplements or vitamins with iron, you may be taking too much. Certain medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), may irritate the lining of your stomach or cause ulcers. This can cause bleeding and metallic-smelling stool.

Blood in stool

Many problems can lead to blood in your stool. Active bleeding appears as bright red, while slow oozing or general irritation can cause black, tar-colored poop.

Irritation of the stomach lining, ulcers, inflammatory bowel disease, infections, cancers of the GI tract, and diverticulosis may all lead to blood in the stool along with a metallic smell.

Digestion problems

Intestinal diseases may cause issues with the absorption of nutrients. One example is celiac disease, an autoimmune disorder that results in poor function of the small intestine’s first portion, leading to less nutrient absorption.

Inflammatory bowel diseases, such as Crohn’s disease, may also affect how well your intestines absorb nutrients. Any disease that affects the absorptive ability of the intestines may lead to higher amounts of iron in stool and a metallic smell.

Infections

Bacteria, viruses, or parasites may cause infections of the GI tract. Sudden infections can lead to a buildup of certain toxins or impact the ability of the intestines to absorb nutrients properly.

If you have a new infection, you may experience abdominal pain, diarrhea, a fever, and/or bloody poop that smells metallic.

Read our guides on different types of stool, stool colors, and healthy vs. unhealthy stool for more.

Managing poop that smells metallic

When you notice that your poop has a metallic smell, there may be some simple solutions.

Following is a step-by-step process for determining the cause of the smell. But start by looking at your stool to make sure there is no blood in it (bright red, black/tarry, or blood clots). If you’ve gone through all the steps and can’t determine why it smells like metal, it’s time to consult with your doctor.

1. Your diet and supplements

If your diet is high in iron-rich foods, consider decreasing the quantity of these foods to reduce iron in your stool.

Also, evaluate any supplements and vitamins you’re taking to possibly reduce the amount of iron – unless you’re taking iron supplements at your doctor’s direction. In that case, discuss this with your doctor before making any changes. Also, make sure to stay hydrated and drink plenty of water. This will prevent bacteria from overgrowing and help keep your bowel movements regular.

2. Medications

Review any medications you take regularly to determine if you are taking in too much iron. Also, make sure you’re taking medications as recommended, as certain medicines may irritate the lining of your stomach and cause bleeding.

As previously mentioned, discuss any concerns about medications with your doctor if you are considering starting a new medication.

3. Manage infections early

If you are concerned that you have an infection (gastroenteritis, food poisoning, or bacterial overgrowth), contact your doctor as soon as possible to start treatment early.

Depending on the cause, infections may require treatment with antibiotics or antiparasitics. Clearing them from your body will help get rid of the metallic smell.

4. What to do about blood in your stool

Be sure to always pay attention to the color and texture of your poop. If you have a large amount of blood or black stool, or you are very tired, see a doctor as soon as possible. This may be a symptom of an ulcer or possibly an early warning sign of cancer.

When you should see a doctor about poop that smells metallic

It’s important to understand when to see a doctor for metallic-smelling poop. There are a few situations when it’s urgent and merits a visit to the emergency room.

You should see a doctor if:

• You’ve noticed a persistent metallic smell despite adjusting your diet or medications;
• You are concerned there is blood in your stool;
• You had recently traveled to a tropical area with new stool irregularities;
• You have new, unintentional weight loss.

You should go to the emergency room if:

• You have a large amount of bright red blood in your stool;
• Your stool is black, and you are extremely tired or have a loss of energy;
• You have abdominal pain and a fever.

Questions to ask your doctor about poop that smells metallic

Metallic-smelling poop can be concerning, so be sure to seek medical guidance. It may be as simple as too much iron in your diet or supplements, but it’s best to find out for sure. Below are a few questions to discuss with your doctor.

• What could be causing my stool to have a metallic smell?
• What do I do if the metallic smell returns?
• When should I be concerned about the metallic smell?
• Should I have an upper endoscopy or a colonoscopy?
• Should I be concerned about my iron levels?

Frequently asked questions: poop that smells metallic

Is metallic-smelling poop a sign of bowel cancer?

If there is blood in your stool along with a metallic smell, it could possibly be a sign of bleeding inside your intestines.

Cancers of the esophagus, stomach, small intestine, and colon can cause bleeding. However, many other causes of blood in the stool are not cancer. Diverticulosis, ulcers, gastritis, and benign tumors can also cause metallic-smelling poop.

What if your poop smells like metal but is not accompanied by blood?

There could be several causes of metallic-smelling poop when there are no signs of blood in your stool. If your stool is black, it could mean there’s blood in it but your intestines have processed it.

If there is no blood and your stool is not black, you may have high iron loads due to supplements, vitamins, or medicines. The bacterial load in your intestines may also be imbalanced, which can cause high iron.

Metallic-smelling poop

By now, you’re probably aware that the cause of a metallic smell is likely due to iron in your poop. High iron levels can be caused by too much iron in your diet, medication side effects, infections, or blood in your stool. Recognizing the possible causes is important to help you remain calm and understand when to talk to a doctor.

General Medicine follows a strict editorial process, including using real experts to write our articles, vetted primary sources, fact-checking, a secondary medical review, and updates as necessary. This article was medically reviewed and fact checked by Dr. Pallabi Sanyal-Dey, MD.

Sources

Cerro, Ariana, and McGreggor Crowley, “Micronutrient Metabolism,” in Beth Frates, et al. (Eds), Essentials of Clinical Nutrition in Healthcare, McGraw Hill, 2024. https://accessmedicine.mhmedical.com/content.aspx?bookid=3462&sectionid=285896225.

National Institutes of Health, “Iron,” Fact Sheet for Health Professionals, October 29, 2024. https://ods.od.nih.gov/factsheets/Iron-HealthProfessional.

Rubin, Deborah C., “Disorders of Absorption,” Harrison’s Principles of Internal Medicine, in Joseph Loscalzo, et al. (Eds) McGraw-Hill Education, 2022. https://accessmedicine.mhmedical.com/content.aspx?bookid=3095&sectionid=265427955.