Our Services
Medical Information
Helpful Resources
Published on: 2/5/2026
A burnt rubber or chemical stool odor is most often linked to three gut issues: malabsorption of fats, sulfur-related digestion from diet or sulfur-producing bacteria, and microbiome imbalance such as dysbiosis or SIBO. There are several factors to consider, and this symptom is often manageable once the cause is identified, but persistent changes or any red flags should be evaluated by a clinician. For key warning signs, what to try now, and which tests and treatments might guide your next steps, see the complete details below.
Noticing that your stool smells like burnt rubber or chemicals can be unsettling. While poop never smells pleasant, a sharp, acrid, or rubber‑like odor is different from normal and often points to something specific happening inside your digestive system.
The good news: in many cases, this symptom is explainable and treatable, especially when you understand the underlying gut issue. Below are three medically recognized gut problems that can cause this strange smell, explained in clear, practical terms—without panic, but without brushing things off either.
Stool odor is influenced by:
A burnt rubber smell usually comes from undigested compounds, especially fats or sulfur-containing substances, being broken down by gut bacteria in abnormal ways.
One of the most common medical reasons for a chemical or burnt rubber smell is malabsorption.
Malabsorption happens when your digestive system does not properly absorb nutrients, particularly fats. Instead of being absorbed, these nutrients pass into the stool, where gut bacteria break them down and release strong-smelling byproducts.
Poorly absorbed fats and proteins can create odors that are:
This is often described as a sharp or industrial smell, not just "bad."
Malabsorption is not something to ignore long-term, because it can lead to vitamin and mineral deficiencies. A doctor can diagnose it with stool tests, blood work, or imaging.
Another major cause of burnt rubber–smelling stool is sulfur.
Sulfur-containing compounds produce gases like hydrogen sulfide, which are responsible for:
In some people, sulfur smells don't come across as "eggy" but instead as burnt rubber or electrical wiring.
Your gut contains bacteria that specialize in breaking down sulfur. If these bacteria become overactive or dominant, sulfur gas production increases. This is directly tied to microbiome health.
Occasional sulfur-smelling stool after certain meals is usually harmless. It becomes more concerning if:
In those cases, it may signal bacterial imbalance, food intolerance, or impaired digestion.
Your gut is home to trillions of bacteria. When that ecosystem is out of balance, it can dramatically change how your stool smells.
Dysbiosis means:
One specific type is Small Intestinal Bacterial Overgrowth (SIBO), where bacteria ferment food too early in digestion.
Imbalanced bacteria produce unusual fermentation byproducts, including:
These can combine into an odor people often describe as burnt rubber, plastic, or metal.
Factors that can disrupt microbiome health include antibiotics, chronic stress, restrictive diets, infections, and underlying gut disease.
A strange stool smell alone does not diagnose a disease. However, persistent changes deserve attention, especially if they last more than a couple of weeks or come with other symptoms.
Speak to a doctor promptly if you notice:
Some gut conditions can be serious or even life-threatening if untreated, so medical guidance matters.
If you're experiencing these symptoms and want immediate guidance, you can get personalized insight by using Ubie's free Medically Approved LLM Symptom Checker Chat Bot, which helps you understand your symptoms and determine whether you should seek medical care.
That said, online tools are not a replacement for a doctor, especially when symptoms are ongoing or worsening.
While you wait to speak with a healthcare professional, general steps that often help include:
If malabsorption, sulfur intolerance, or microbiome imbalance is suspected, targeted treatment—not guesswork—is the safest approach.
A burnt rubber smell in your stool is unusual, but it's often linked to:
Many of these conditions are manageable once properly diagnosed. The key is not ignoring persistent changes and speaking to a doctor about anything that could be serious or life-threatening.
Your gut has ways of signaling when something's off. Paying attention—and getting professional guidance when needed—is the smartest next step.
(References)
* Blachier, F., et al. (2019). Hydrogen sulfide in the gastrointestinal tract: a new target for drug development? *British Journal of Pharmacology*, *176*(5), 651-663. doi: 10.1111/bph.14589.
* Pimentel, M., et al. (2020). Hydrogen Sulfide Small Intestinal Bacterial Overgrowth. *The American Journal of Gastroenterology*, *115*(9), 1391-1393. doi: 10.14309/ajg.0000000000000725.
* Likhodii, S., et al. (2018). Fecal volatile organic compounds as biomarkers of gut health and disease. *Metabolites*, *8*(3), 56. doi: 10.3390/metabo8030056.
* Lohr, J. M., et al. (2017). Exocrine pancreatic insufficiency: A neglected disease? *Digestive Diseases*, *35*(2), 127-133. doi: 10.1159/000450942.
* Ahmed, I., et al. (2016). Fecal Volatile Organic Compounds as Biomarkers of Inflammatory Bowel Disease. *Journal of Crohn's and Colitis*, *10*(10), 1214-1225. doi: 10.1093/ecco-jcc/jjw080.
We would love to help them too.
For First Time Users
We provide a database of explanations from real doctors on a range of medical topics. Get started by exploring our library of questions and topics you want to learn more about.
Was this page helpful?
Purpose and positioning of servicesUbie Doctor's Note is a service for informational purposes. The provision of information by physicians, medical professionals, etc. is not a medical treatment. If medical treatment is required, please consult your doctor or medical institution. We strive to provide reliable and accurate information, but we do not guarantee the completeness of the content. If you find any errors in the information, please contact us.