Common Causes (Ranked by Likelihood)
Most people don't deliberately clean inside their belly button during showers. Dead skin, sweat, oils, and lint accumulate in the folds. A 2012 study from North Carolina State found an average of 67 species of bacteria in belly buttons, including species that produce skatole, indole, and short-chain fatty acids — all of which smell terrible. The warm, moist, oxygen-poor environment is ideal for anaerobic bacteria.
Candida yeast thrives in warm, moist skin folds — and the belly button is a prime location. Yeast infections produce a sour, bread-like, or sometimes fecal-smelling odor along with redness and itching. People with diabetes, obesity (deeper skin folds), or who take antibiotics are at higher risk. The infection can persist even with regular washing if not treated with antifungals.
Belly button piercings are notoriously prone to infection because the area stays moist and is subjected to friction from clothing. An infected piercing produces discharge (clear, white, yellow, or green) that can smell terrible. Even healed piercings accumulate sebum and dead skin in the piercing canal, producing a concentrated foul smell when squeezed.
In rare cases, a foul-smelling belly button can indicate an underlying structural problem. A urachal cyst (remnant of fetal development connecting the belly button to the bladder) can become infected and drain foul-smelling fluid. An umbilical hernia or granuloma can also trap fluid and bacteria. These conditions produce persistent smell and discharge that doesn't respond to surface cleaning.
How to Fix It
Clean Your Belly Button Properly
$0Fixes the cause 95% of the time.
- 1In the shower, dip a cotton swab (Q-tip) or finger in soapy water and gently clean inside all folds of the belly button.
- 2Rotate the swab to collect all debris — you may be surprised at what comes out.
- 3Rinse thoroughly with water and PAT DRY completely — moisture left behind feeds bacteria and yeast.
- 4Do this 2-3 times per week as maintenance. Daily if you're prone to buildup.
Treat Yeast Infection
$5-15For persistent smell with redness and itching.
- 1Apply an OTC antifungal cream (clotrimazole or miconazole) inside the belly button twice daily for 1-2 weeks.
- 2Keep the area completely dry — pat dry after showering and consider a light dusting of antifungal powder.
- 3Avoid tight-fitting clothing that creates moisture and friction over the area.
- 4If it doesn't clear in 2 weeks, see a doctor — you may need a prescription-strength antifungal.
See a Doctor
$100-300For infected piercings, persistent discharge, or suspected structural issue.
- 1Infected piercings may need oral antibiotics — don't just remove the jewelry (this can trap the infection).
- 2Persistent discharge from deep inside the belly button warrants an ultrasound to check for urachal cyst or other structural issues.
- 3A doctor can culture any discharge to identify the specific bacteria or fungus and prescribe targeted treatment.
- 4Umbilical granulomas are treated with silver nitrate application — a quick in-office procedure.
When to Call a Professional
Persistent foul discharge that keeps returning — may indicate a urachal cyst or fistula. See a doctor.
Red, hot, swollen belly button with fever — bacterial infection needing antibiotics.
Infected piercing with spreading redness — cellulitis risk. See a doctor promptly.
Blood-tinged discharge from the belly button — needs medical evaluation.
How to Prevent It
Clean your belly button 2-3 times per week with a soapy cotton swab.
Dry thoroughly after showering — moisture is the primary enabler of bacteria and yeast.
Avoid picking at the belly button — can introduce bacteria and cause micro-tears.
Clean piercings daily with saline solution.
Change undershirts and tight clothing daily — lint and fabric debris contribute to buildup.
The Belly Button Microbiome: A Hidden Ecosystem
The Belly Button Biodiversity Project at North Carolina State University sampled 60 belly buttons and found 2,368 species of bacteria — 1,458 of which may be new to science. The average belly button harbored 67 species. Despite this diversity, most of the biomass was dominated by a few common skin bacteria: Staphylococcus, Corynebacterium, and Micrococcus.
The reason belly buttons accumulate such diverse microbial communities is their unique microenvironment. The deep, folded structure creates an oxygen-poor, warm, moist habitat that's protected from UV light and mechanical disruption (unlike most skin surfaces that are regularly exposed to air and friction). This makes the belly button more similar to the gut or groin microbiome than to surrounding abdominal skin.
The fecal-like smell specifically comes from bacterial production of skatole (3-methylindole) and indole — compounds produced when bacteria break down the amino acid tryptophan from dead skin proteins. These are the same compounds, at higher concentrations, that give feces their characteristic odor. The belly button environment is particularly conducive to the anaerobic bacteria that produce these compounds.
Frequently Asked Questions
It's a warm, dark, moist cavity that traps dead skin, sweat, oils, and lint. Bacteria break this down into foul-smelling compounds including skatole (the same compound in feces). The fix is simple: clean inside with a soapy cotton swab 2-3 times per week and dry thoroughly.
Simple bacterial or yeast infections are easily treated with OTC products. However, deep infections, especially around piercings, can develop into cellulitis (spreading skin infection) if untreated. Signs of a serious infection include spreading redness, fever, and warmth — see a doctor if these occur.
Piercings accumulate sebum, dead skin, and bacteria in the piercing channel. This buildup decomposes and produces an extremely concentrated odor — often described as the worst smell imaginable. Regular cleaning with saline solution prevents buildup. The smell doesn't necessarily mean the piercing is infected.
See a doctor if: the smell doesn't improve with proper cleaning, there's persistent discharge, the area is red/swollen/painful, or you have fever. Most cases are resolved with improved hygiene within a few days.