A fecal smell coming from your vagina usually has a straightforward explanation, and most causes are fixable. The smell can come from something as simple as sweat and bacteria in the skin folds around your vulva, fecal bacteria that migrated from the anus, or a forgotten tampon. Less commonly, it points to a medical condition like an abnormal connection between your rectum and vagina. Understanding the most likely causes helps you figure out whether this is something you can address at home or something that needs a doctor’s attention.
Sweat and Bacteria in the Groin
The skin around your vulva and inner thighs is packed with a specific type of sweat gland found only in areas like the groin, armpits, and around the nipples. These glands produce a thick, protein-rich sweat that is odorless on its own. The smell develops when bacteria on the skin, particularly a group called Corynebacterium, break down those proteins into ammonia and short-chain fatty acids. The result can range from a sharp, sour smell to something that resembles feces, especially after exercise, a long day in tight clothing, or in hot weather.
This type of odor lives on the skin, not inside the vagina. Washing the outer vulva and groin folds with warm water (or a gentle, unscented cleanser) and wearing breathable cotton underwear typically takes care of it. If the smell is persistent and strong despite good hygiene, a condition called bromhidrosis may be involved, which is essentially chronic body odor from overactive sweat glands. A dermatologist can help with treatment options.
Fecal Bacteria Near the Vaginal Opening
The anus and vaginal opening sit close together, separated by only a small strip of skin called the perineum. Trace amounts of fecal matter can transfer to the vulva during wiping, especially if toilet paper drags across the skin rather than lifting away. This doesn’t just cause odor. It’s also one of the main ways bacteria from the bowel reach the urinary tract and cause infections.
The common advice is to wipe front to back, and that’s reasonable, but the real goal is simply to avoid dragging fecal matter forward toward the vaginal and urethral openings. You can also wipe the anal area separately without crossing the perineum at all. A quick rinse with water after a bowel movement, such as with a bidet or peri bottle, is one of the most effective ways to keep fecal bacteria from lingering on nearby skin.
A Forgotten Tampon or Other Retained Object
A tampon that’s been left in too long is one of the more common causes of a sudden, overwhelming foul smell from the vagina. It happens more often than you might think, particularly when a second tampon is inserted before the first is removed, or when a tampon from the end of a period is simply forgotten.
According to the NHS, if a tampon stays inside for an extended period, you’ll typically notice a strong smell and unpleasant discharge. The odor comes from bacteria breaking down the trapped blood and vaginal fluids. People frequently describe it as smelling like rotting garbage or feces. If you suspect a retained tampon, try to remove it yourself by bearing down and reaching in with clean fingers. If you can’t reach it or aren’t sure if something is there, a healthcare provider can check and remove it quickly. The smell resolves fast once the object is out.
Rectovaginal Fistula
If you consistently smell feces from your vagina, or if you notice stool or gas actually passing through your vagina, the cause may be a rectovaginal fistula. This is an abnormal tunnel that forms between the rectum and the vagina, allowing bowel contents to leak through. It’s not common, but it’s the condition most directly responsible for a true fecal smell originating from inside the vagina.
The most frequent cause is a childbirth injury, particularly vaginal tears or episiotomies that don’t heal properly. Other causes include Crohn’s disease and ulcerative colitis (which can erode the tissue between the rectum and vagina over time), complications from diverticulitis, pelvic radiation therapy, and previous pelvic or abdominal surgeries. Cervical or colorectal cancer can also cause one, though this is rarer.
Symptoms beyond odor include passing gas through the vagina, visible stool in vaginal discharge, and recurrent vaginal or urinary tract infections. A rectovaginal fistula won’t heal on its own in most cases. Surgical repair is the standard treatment, and the success rate depends on the size and location of the fistula and the underlying cause.
Bowel Leakage You May Not Notice
Some people experience small amounts of stool or mucus leaking from the anus without feeling it happen, a form of fecal incontinence called passive incontinence. Because the leakage can be so minor, it may show up only as streaks or stains on underwear, and the smell can seem like it’s coming from the vagina when it’s actually coming from the anus or perineal skin.
Several things can cause this. Hemorrhoids can prevent the anal muscles from closing completely, allowing small amounts of stool or mucus to seep out. A rectocele, where the rectum bulges into the back wall of the vagina, can trap stool and make it harder to fully empty the bowel. Chronic constipation weakens the rectal muscles over time, and watery stool can leak around hard, impacted stool. Nerve damage from childbirth, diabetes, or spinal injuries can also reduce your ability to sense and control what’s passing through the anus.
If you’re noticing staining on your underwear along with the smell, this is worth bringing up with a doctor. Pelvic floor physical therapy helps many people regain muscle control, and treating the underlying cause (such as constipation or hemorrhoids) often resolves the leakage.
Bacterial Vaginosis and Other Infections
Bacterial vaginosis, the most common vaginal infection, produces a smell that’s more commonly described as fishy than fecal. But strong vaginal odors don’t always fit neatly into one category, and some people perceive the smell differently. BV happens when the normal balance of bacteria in the vagina shifts, allowing certain species to overgrow. It often comes with a thin, grayish-white discharge.
A healthcare provider can test for BV with a pelvic exam, a pH test of the vaginal fluid (BV raises acidity), a microscope slide to look for characteristic bacterial cells, and a “whiff test” where the sample is treated with a chemical to see if it produces a fishy odor. These same visits can also screen for sexually transmitted infections and cervicitis, which can cause abnormal discharge and odor as well.
How to Tell What’s Causing the Smell
A few details can help you narrow it down before you see anyone. If the smell is strongest in skin folds and goes away after a shower, sweat and surface bacteria are the most likely culprits. If it appeared suddenly and you’ve recently had your period, check for a retained tampon. If you notice gas or stool passing through your vagina, a fistula is the primary concern. If you see staining in your underwear throughout the day, bowel leakage is worth investigating.
Persistent vaginal odor that doesn’t improve with external hygiene, or any odor accompanied by unusual discharge, pelvic pain, or fever, warrants a medical evaluation. A careful history, physical exam, and targeted lab tests are far more reliable than trying to self-diagnose based on the type of smell alone.