Why Your Poop Smell Like Coffee: Causes & How to Fix

Key takeaways:

• When bacteria break down food in your gut, they produce gasses like methane and hydrogen sulfide, which give poop its odor.
• Caffeine in coffee speeds digestion, which means bacteria have less time to produce gas.
• Chlorogenic acid, another ingredient in coffee, can reduce the number of bacteria in the gut, which results in less gas.

The process of digestion relies on the bacteria in your gut. The beneficial bacteria in your gut produce gasses like methane and hydrogen sulfide while breaking down your food. Caffeine in coffee speeds digestion, giving bacteria less time to process food and make gas, which usually gives poop a foul odor.

Coffee also contains chlorogenic acid, which slows down carbohydrate absorption in the gut. It also reduces the number of harmful bacteria in your gut, which may alter the character of your poop’s smell. So, if your poop smells like coffee, it may be because of coffee itself. If you’re not a coffee drinker, though, a coffee-like smell is rare and may be due to a condition like diabetic ketoacidosis.

Is it normal for your poop to smell like coffee?

If you drink coffee, it can be normal for its smell to appear in your stool. Your poop’s smell is influenced by the foods you eat and by the gasses produced by your gut bacteria. When you drink coffee, the caffeine speeds up the digestive tract, so there is not enough time for your food to digest properly. As a result, you may have less gas produced by bacteria, and your poop may smell more like the coffee you just drank.

Causes of poop that smells like coffee

Multiple factors influence the smell of your poop. Poop generally gets its distinctive smell from the food you digest and from the gasses produced by the gut bacteria. Although many people occasionally think their poop smells like coffee, others may smell nothing at all.

Drinking a lot of coffee

Your poop’s color, consistency, and smell have a lot to do with what occurs during digestion. Since the caffeine in coffee speeds up the digestive tract, your food won’t be wholly digested, which may contribute to retaining the coffee smell. If you have had a lot of coffee and nothing else to eat, your poop and urine will be concentrated and may smell like coffee.

Acidity of coffee

The acidic pH of coffee triggers the production of a hormone in the stomach called gastrin. Gastrin stimulates specialized cells in the stomach to secrete acid. Acid can eliminate harmful bacteria in the gut that would otherwise make your poop smell foul.

Polyphenols

Coffee contains a thousand chemicals called polyphenols that give it its characteristic flavor and smell. Hydroxycinnamic acid is a polyphenol that breaks down into a substance eliminated as waste in your urine. This metabolite causes your urine and other bodily fluids to smell like coffee and can potentially cause a coffee smell in your poop.

Chlorogenic acid

Chlorogenic acid is a component of coffee. It is an antioxidant and reduces the number of bacteria in your gut, which reduces fecal odor.

Dehydration

Coffee can speed up the movement of the muscles of the large intestine, increasing the speed of transit. This does not allow enough time for the reabsorption of water in stool. With water loss, you may become dehydrated. If you are very dehydrated, your body fluids may become concentrated, potentially leading to stools that smell strongly of coffee.

Changes in your sense of smell

You can have changes in your sense of smell for many reasons, including nasal congestion or competing odors. This can affect the way you perceive the smell of your stool.

Urinary tract infection

Some urinary tract infections are caused by bacteria that produce a sweet or coffee-like smell to body fluids, including stool.

Diabetic ketoacidosis

Diabetic ketoacidosis occurs in people with diabetes who have extremely high blood sugar. The sugar spills into the urine and draws water from the body in a diuretic effect. When someone has diabetic ketoacidosis, their urine is often described as “fruity.” All of the body fluids can be affected, depending on volume status.

Treatment options for poop that smells like coffee

If your poop smells like coffee, you may be concerned. Stool odor results from the food you eat and your gut microbiome, which refers to the beneficial bacteria that live in your gut and help with digestion and immunity. If the coffee smell bothers you, there are a few things you can do, including some simple lifestyle changes.

Monitor your coffee intake

How much coffee do you drink? You may want to cut back if you drink multiple cups of coffee throughout the day. If you only have a cup of coffee in the morning, monitor how long it is before you smell coffee in your poop.

Increase your fluid intake

You should also increase your fluid intake. By increasing the amount of water you drink in addition to your coffee, you will have a lower concentration of coffee in your waste.

Switch to decaffeinated coffee

Try a decaffeinated coffee. Caffeine is a bowel stimulant. A rapid passage of food through your gut may not allow for adequate absorption, changing the bacterial balance in the gut. Since bacteria release substances that can cause various smells, the type of bacteria in your gut will contribute to the smell of your poop.

When you should see a doctor about poop that smells like coffee

If you have been drinking coffee and notice a coffee smell in your poop, then your coffee consumption is likely to be the cause. In most cases, this smell should resolve when you stop drinking coffee. If the odor persists and you don’t recall it happening in the past, it might be a cause for concern. You should take note of any other symptoms like changes in frequency or consistency of your stool, abdominal pain, nausea, vomiting, gas, and change in stool color.

You should see a doctor if:

• You experience nausea alongside poop that smells like coffee.
• You have excessive flatulence.
• There is a change in the color or texture of your stool.
• You experience constipation or diarrhea (frequent, loose stools).

You should go to the emergency room if:

• You find blood in your stool or pass red, black, or tarry stools.
• Your stools look like coffee grounds.
• You experience severe abdominal pain.
• You have a fever or chills.
• You are vomiting.

Questions to ask your doctor about poop that smells like coffee

• Am I consuming too much coffee?
• How does the quality of the coffee I drink affect my stools?
• Is there a possible underlying health condition contributing to the smell of my poop?
• Are there tests that can be performed to better understand the issue?

Frequently asked questions: poop that smells like coffee

It is natural to wonder about a change in your stool, particularly if it is something you haven’t experienced before. While a change in smell isn’t always a cause for concern, you probably have some of the same questions others with this problem have asked.

Why would your poop smell like coffee if you don’t drink coffee?

Everyone perceives certain smells differently, so what seems like coffee to you may simply be a similar smell. Many smells are nearly alike, probably due to a comparable combination of phenols and gasses. See your doctor if the smell persists and you’ve never noticed it before.

Is poop that smells like coffee a sign of diabetes?

Sometimes, people confuse the smell of coffee with the fruity or sweet smell of diabetic ketoacidosis. Diabetic ketoacidosis is caused by high blood sugar, and the related smells are often the first time someone with diabetes becomes aware of their condition. Other signs you should watch for if you are concerned about diabetes are frequent urination, excessive thirst, and abdominal pain.

Final thoughts on coffee-smelling poop

The smell of your poop depends upon the food you eat and the gasses and other chemical compounds released by your gut bacteria. Your sense of smell also plays a role in what you perceive. There is no cause for concern in most cases, and the odor will likely resolve on its own. If you have other concerning symptoms like bloody stool or abdominal pain or if the smell lasts for several days, you may want to call your doctor for an evaluation.

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. Poushali Bhattacharjee, MD.

Sources

Bekedam, E Koen, et al. “Incorporation of chlorogenic acids in coffee brew melanoidins.” Journal of agricultural and food chemistry vol. 56,6 (2008): 2055-63. doi:10.1021/jf073157k, https://pubmed.ncbi.nlm.nih.gov/18290625/.

Butt, Masood Sadiq, and M Tauseef Sultan. “Coffee and its consumption: benefits and risks.” Critical reviews in food science and nutrition vol. 51,4 (2011): 363-73. doi:10.1080/1040839090358641, https://pubmed.ncbi.nlm.nih.gov/21432699/.

Chan, Daniel K et al. “Diagnosing gastrointestinal illnesses using fecal headspace volatile organic compounds.” World journal of gastroenterology vol. 22,4 (2016): 1639-49. doi:10.3748/wjg.v22.i4.1639, https://pmc.ncbi.nlm.nih.gov/articles/PMC4721995/.

Sc, Yenisetti, and Muralidhara. “Beneficial Role of Coffee and Caffeine in Neurodegenerative Diseases: A Minireview.” AIMS public health vol. 3,2 407-422. 20 Jun. 2016, doi:10.3934/publichealth.2016.2.407, https://pmc.ncbi.nlm.nih.gov/articles/PMC5690364/.

Vermeer, Eva, et al. “Wake up and smell the coffee: The potential of faecal volatile organic compounds in paediatric inflammatory bowel disease.” United European gastroenterology journal vol. 12,6 (2024): 660-661. doi:10.1002/ueg2.12618, https://pmc.ncbi.nlm.nih.gov/articles/PMC11249820/.