Persistent fecal odor around the anus is almost always caused by incomplete cleaning, trapped moisture, or minor fecal leakage you may not even notice. The fix usually comes down to better cleaning technique, keeping the area dry, and choosing the right products. In some cases, an underlying condition is responsible, and no amount of hygiene will solve it until that’s addressed.
Why the Smell Lingers
The two main compounds responsible for fecal odor are indole and skatole, nitrogen-based chemicals produced by gut bacteria as they break down food. These compounds cling to skin easily and aren’t fully removed by dry wiping alone. The perianal area also has folds and creases where trace amounts of stool can hide, and the warm, moist environment lets bacteria thrive and continue producing odor even after you’ve left the bathroom.
Sweat makes the problem worse. When moisture sits against skin in a warm area with residual fecal matter, bacteria multiply quickly. This is why the smell can seem to come back or intensify throughout the day, especially during physical activity or in hot weather.
Cleaning That Actually Works
Dry toilet paper smears more than it removes. A 2021 study in the Journal of Water and Health found that using a bidet significantly reduced fecal matter left on skin compared to toilet paper alone. If you don’t have a bidet, a portable bidet bottle (sometimes called a peri bottle) costs a few dollars and does the same job. You can also dampen plain, unscented toilet paper with water for a quick rinse-and-pat approach.
After washing with water, pat the area completely dry with a clean tissue or soft cloth. Leaving moisture behind creates the exact conditions bacteria love. Some people find that a quick pass with dry toilet paper after the water rinse catches any remaining dampness.
If you’re away from home, unscented baby wipes work as a backup, but they shouldn’t be your daily go-to. Even “sensitive skin” wipes can contain preservatives that irritate perianal skin over time. Plain water is the gold standard.
Products to Avoid
It’s tempting to reach for scented soaps, body washes, or deodorant sprays to mask the smell, but these often make things worse. Cleveland Clinic specifically advises against using soap on the perianal area. The skin there is unusually sensitive, and fragrances, dyes, and chemical deodorants can trigger irritation or allergic reactions. Irritated skin becomes inflamed, can crack or weep, and actually traps more odor-causing bacteria.
Scented toilet paper, bubble baths, scented powders, and perfumed creams all carry the same risk. If you feel you need a cleanser, use a small amount of unscented, pH-balanced wash and rinse thoroughly. But water alone handles the job for most people.
Keep the Area Dry Throughout the Day
Cotton underwear is the single best fabric choice for reducing moisture buildup. Cotton breathes and wicks sweat away from the skin, while synthetic fabrics trap heat and moisture. Cleveland Clinic notes that even underwear marketed with a “cotton crotch panel” doesn’t offer the same protection as 100% cotton, because the surrounding synthetic fabric still limits airflow.
Loose-fitting underwear and pants help too. Tight clothing presses fabric into the area and prevents air circulation, which keeps everything warm and damp. If you sweat heavily, changing your underwear midday can make a noticeable difference. Some people also benefit from a light dusting of unscented cornstarch-based powder (not talc) to absorb excess moisture, though this works best on fully dry skin.
Fecal Leakage You Might Not Notice
If you clean thoroughly and still notice a smell, minor fecal seepage could be the cause. This is more common than most people realize. Hemorrhoids can prevent the muscles around the anus from closing completely, allowing small amounts of stool or mucus to leak out without any sensation. You may only notice it as a faint odor or slight staining on your underwear.
Other causes of minor leakage include weakened pelvic floor muscles (from childbirth, aging, or chronic straining), loose stools that are harder to fully contain, and dietary factors that produce excess mucus. High-fiber foods can firm up stool and reduce the likelihood of seepage, since solid stool is easier for the sphincter muscles to hold back than soft or liquid stool.
Pelvic floor exercises, sometimes called Kegels, strengthen the muscles that control the anal sphincter. Done consistently over several weeks, they can improve your ability to fully close the anus and reduce passive leakage.
Dietary Factors That Affect Odor
What you eat directly changes the intensity of fecal odor. Sulfur-rich foods like eggs, cruciferous vegetables (broccoli, cabbage, cauliflower), garlic, and red meat produce more hydrogen sulfide and other pungent gases during digestion. This doesn’t mean you need to eliminate these foods, but if odor is a persistent concern, tracking whether certain meals make it worse can help you adjust.
Adequate water intake keeps stool softer and easier to pass completely, reducing the chance that residue stays behind. Probiotic-rich foods like yogurt and fermented vegetables support a balanced gut microbiome, which can reduce the production of particularly foul-smelling compounds.
When a Medical Condition Is the Cause
Persistent odor that doesn’t respond to hygiene changes may point to something that needs medical attention. Anal fissures (small tears in the lining) and fistulas (abnormal tunnels between the bowel and skin) can leak discharge that carries a strong smell. Rectal prolapse, inflammatory bowel disease, and chronic diarrhea from any cause can also make odor difficult to control on your own.
A rare metabolic condition called trimethylaminuria causes the body to produce a persistent fishy or fecal odor that comes from the skin, breath, and urine. It’s caused by the body’s inability to break down a specific compound found in many foods, particularly fish, eggs, and legumes. The condition can be mild and intermittent, which makes it easy to miss. Diagnosis involves a urine test after eating a meal high in the trigger compound, and the test sometimes needs to be repeated during a period when the odor is most noticeable.
Signs that suggest a medical evaluation would be helpful include visible blood on toilet paper or in stool, mucus or discharge you can see on your underwear, odor that persists no matter what hygiene routine you follow, noticeable loss of bowel control, and any new lumps, swelling, or pain around the anus.