An unusual smell from stool, such as one resembling mothballs, can be concerning. While normal bowel movements possess an inherent odor, significant deviations can signal various changes within the body. This article explores factors that might contribute to a mothball-like stool odor, covering causes from everyday dietary influences to underlying health conditions.
Understanding the Odor and Normal Bowel Habits
A “mothball” smell in stool often points to a strong, chemical, or unusually pungent odor. This aroma links to compounds like indole and skatole, produced when gut bacteria break down tryptophan, an amino acid in protein-rich foods. These compounds can mimic the characteristic scent of naphthalene, the chemical associated with mothballs.
Normal stool odor is a natural outcome of the digestive process, influenced by the diverse community of bacteria in the gut, known as the microbiome. These bacteria ferment undigested food components, releasing various gases and volatile compounds that contribute to the stool’s smell. Stool consistency and composition can fluctuate daily, reflecting recent dietary intake and hydration.
Everyday Causes of Unusual Stool Odor
Dietary choices are a frequent and often easily modifiable cause of changes in stool odor. Foods rich in sulfur compounds, such as cruciferous vegetables like broccoli, cauliflower, cabbage, and kale, as well as eggs, meat, and dairy products, can lead to a more pungent, sometimes “rotten egg-like” or chemical smell in stool. This occurs as gut bacteria process these sulfur-containing components, releasing sulfur gases. Consuming a diet high in protein can also increase the production of indole and skatole, contributing to a stronger, more unusual odor.
Highly processed foods and artificial sweeteners can also alter stool odor. These substances may be difficult for the digestive system to break down completely, leading to increased fermentation by gut bacteria and the production of various gases. Dehydration can concentrate waste products in the colon, intensifying stool odor as the body reabsorbs more water. A rapid transit time, where food moves quickly through the digestive system, can similarly affect odor by altering the balance of bacterial activity and fermentation.
Underlying Health Conditions and Medications
Certain medical conditions can significantly alter stool composition and odor. Malabsorption syndromes, where the body struggles to absorb nutrients, often result in foul-smelling, fatty stools (steatorrhea). Conditions like celiac disease can damage the small intestine lining, impairing nutrient absorption and leading to greasy, unpleasant-smelling stool. Other malabsorption issues include Crohn’s disease, ulcerative colitis, pancreatic insufficiency, and lactose intolerance, all of which can cause undigested food components to ferment in the colon, producing strong odors.
Intestinal infections are a common cause of unusual stool odor. Bacterial infections like Clostridium difficile and Salmonella, or parasitic infections such as Giardiasis, can lead to distinctively foul-smelling diarrhea. These pathogens disrupt the gut microbiome and digestive processes. Metabolic disorders, though less common, can sometimes impact the body’s chemical balance, potentially leading to unusual stool odors.
Medications can also change stool odor. Antibiotics are known for this effect, as they can disrupt the balance of bacteria in the gut. This alteration can lead to temporary changes in stool consistency and odor, often resolving once the course is completed. Some supplements, especially those high in sulfates, can also contribute to increased sulfur gas production by gut bacteria, resulting in a more pungent stool smell.
When to Consult a Healthcare Professional
While occasional changes in stool odor are common and often linked to diet, certain accompanying symptoms warrant professional medical evaluation. If an unusual stool odor, particularly one described as mothball-like, persists for more than 48 hours or is accompanied by other concerning signs, consult a healthcare provider. Such “red flag” symptoms include persistent changes in stool consistency, like chronic diarrhea or constipation, or noticeable changes in stool color such as black, tarry, or pale stools.
Additional symptoms that should prompt a medical visit are unexplained weight loss, recurring abdominal pain, fever, nausea, or vomiting. Blood or mucus in the stool, as well as sudden bowel incontinence, are also serious indicators. These symptoms, when combined with an unusual stool odor, may suggest an underlying condition that needs accurate diagnosis and appropriate treatment.