Why do I have constantly wet underwear with a strong ammonia smell?

wet undies
Ask The Doctor > Urinary Tract Infection > Why do I have constantly wet underwear with a strong ammonia smell?


Patient: I constantly have wet undies and it is embarrassing and I can’t figure out what’s going on. This has been going on for almost a year. There is no vaginal discharge that I can physically see: like clumpy, thick, mucous, etc. The only possibility of a discharge is the discoloration that is happening to my underwear if I don’t wear a pad or pantyliner to protect them. I notice a yellow-grey stain on them. And this is an every day thing, not just right before or after my period or anything. I don’t know if the wetness (and the stain in my underwear) is coming from my vagina or urethra. But there is a strong ammonia smell in my underwear after a few hours of wearing a clean pair of panties. However, the general wetness I experience starts as soon as 10 minutes after putting them on. If it was just wetness going on with no odor, I’d think it was just sweat… and that would be fine. But the strong ammonia smell is what I can’t figure out. I’m clean shaven down below. I thought if the odor had nothing to “grab” onto, it would solve the problem, but it hasn’t. I’m 27. Female. I’m not pregnant, never been pregnant. I’ve been on the pill (Yasmin) for 5 years. I am overweight and have been all my life, but I never experienced this before. I’m currently not sexually active and haven’t been for over a year. I’ve been trying everything: changing my diet, drinking water ALL the time, cutting out soda, taking vitamins… which I do normally. What’s going on?

Doctor: Thank you for your question. I know it can be frustrating to have constantly wet undies. Your discharge could be coming from either the vagina or urethra. It is difficult to be certain of this without a physical exam. The ammonia-like odour that you have noticed may indicate that you may be suffering from a sub-clinical urinary tract infection or vaginal infection. What this means is that you may have have an infection in these areas but the symptoms of dysuria, urgency and blood in the urine may not be present, yet. Please see your doctor to conduct an exam as well as urine test to determine if you have a sub-clinical infection. Once diagnosed, you will need to be treated with a course of antibiotics to clear this infection. Thank you for choosing Ask The Doctor.

Comments / Follow Ups

Doctor: Yes, it is possible to be due to hormones. The patient in the question is talking about an ammonical smell which makes me suspect an Urinary tract infection with some dribbling of urine.

The urine is broken down by bacteria which can break down ammonia and cause the smell. A physical defect in the urethra or incontinence can also cause the underwear wetness.

The hormonal level changes can cause increased secretion from the vagina. This is what might be causing the wetness. Another cause can be sweating which occurs in some people from the area in the groin.

If the problem of wet undies continues, you should see a gynecologist and if the gynecologist is not able to reach a conclusion, please see a general physician for further guidance.


The vagina houses various good bacteria that maintain an acidic pH, thereby preventing onset of vaginal infections. However, if the pH balance is disturbed, an infection-prone zone is created. Sometimes infection sets in along with foul odor. The foul, ammonia-like smell emanating from vagina can prove to be quite disconcerting for many women. Embarrassment sets in because they quickly link ammonia smelling discharge to poor personal hygiene. However, it is important to remember that very rarely is inadequate hygiene level the cause for smelly discharge. So then what causes the vaginal discharge to smell like ammonia?


  • Bacterial Vaginosis
  • Dietary Intake
  • Menopause
  • Pregnancy
  • Excessive Sweating
  • Washing Panties with Bleach

» Conditions Resulting in Ammonia Smelling Discharge «

Bacterial Vaginosis (BV)

This is one of the most common infections plaguing the female reproductive system. If your vaginal discharge is watery, white or gray with a fishy smell, you may have contracted bacterial vaginosis. BV can also be accompanied by pain, itching and/or burning.
When Not to Panic

► Vaginal discharge is a natural and essential phenomenon of the body. It’s the way of the body to keep the vaginal region healthy and clean.

► Vaginal fluid is nothing but the collection of old cells that previously lined the vagina and which are now sent out of the body.

► Normally the vaginal discharge is clear or milky white, however, its color and viscosity changes with one’s monthly menstrual cycle. Moreover, on ovulation the vaginal discharge becomes thicker, so also when a woman is sexually excited, pregnant or breastfeeding. So if the viscosity of your discharge changes, don’t get worried.

► The amount of vaginal discharge released varies from one woman to another. So if you feel your body is releasing more vaginal discharge it’s completely normal.

► Every woman has a unique vaginal scent. It’s something that is natural and is distinctive to each woman. Some studies also say that the natural scent of vaginal discharge is what makes the man feel even more ‘turned on’ when a woman is the most fertile. So if your discharge has a distinctive mild odor (not foul), it’s nothing to be concerned about.

What exactly causes BV and how is not very clear until now. Nevertheless, it has been observed that occurrence of BV has connection with an imbalance of bacterial concentration in the vaginal region. Normally, a woman’s genital area is supplied with a combination of good and bad bacteria, wherein the good outnumber the bad. These good bacteria are seen to fight off unwanted foreign and potentially dangerous bacteria. If there is any kind of imbalance in the ratio of good and bad bacteria in the vaginal area, be it too much or too little, the condition of bacterial vaginosis is triggered. The bad bacteria take over and convert nitrogen into ammonia compounds, thereby causing the foul ammonia odor. BV cannot be caught during sexual intercourse, or from some public toilet or swimming pool. However, it is also observed to occur after a person has had intercourse with a new partner or multiple partners. The reason is unknown.

Prevention and Treatment
Avoiding multiple sex partners, unprotected sex, intrauterine devices (IUD), vaginal douching, smoking and application of vaginal deodorants or perfumed soaps, can help reduce the incidence of BV. However, those that refrain from the mentioned activities are also sometimes seen to be affected by this condition. Most of the time, BV clears off on its own, and when it doesn’t antibiotics like metronidazole or clindamycin are available to help treat it. Wearing a pad during the day can help curb the foul odor, until the condition clears. However, for pregnant women the mode of treatment will be different. As the complications (premature delivery, etc.) of this condition increase during pregnancy, one should visit the obstetrician immediately.

Dietary Intake

Did you know the constituents of your diet can also spearhead this foul odor? Well, it’s true! One of the causes of ammonia smell down there can also be linked to one’s dietary intake of nitrogenous foods. The foul odor is mistaken to be from the vaginal discharge, but actually is from the foul-smelling urine (containing lots of ammonia and urea) that trickles and stains the undergarment.

Vegetables like broccoli, asparagus and other nitrogen-rich vegetables are seen to be the culprits. The leftover oxalates from the asparagus are seen to cause the fishy odor in the urine. Moreover, food items like meat, eggs and other high protein foods contain large amounts of nitrogen and cause excess ammonia and urea to get excreted in the urine. This results in ammonia-smelling urine. Several food items we consume also have arduous oils that end up being secreted in the sweat.

Prevention and Treatment
To prevent this condition, make sure you eat a healthy and balanced meal, with the right balance of vitamins, minerals, proteins, carbohydrates, etc. This will strengthen your immune system and arm your body against any infections. Those who suddenly shift to a vegetarian diet, tend to consume large amounts of leafy vegetables which cause ammonia-like smell in the urine. So consume everything in moderation. Moreover, consuming yogurt on a regular basis will also help treat the foul odor.


As a woman enters menopause, the body begins to experience change in several ways. During menopause the ovaries quit producing the hormone estrogen and progesterone. Besides the basic menopausal symptoms of hot flashes, mood swings, urinary leakage, etc. ammonia-like odor is also experienced.

During menopause, women are seen to not take in enough water. This lack of adequate water results in formation of concentrated urine which imparts a highly stronger smell or odor. Oft, women mistake the ammonia smell to come from urine left behind on the panties, to be coming from the vaginal discharge. Bacteria convert the chemicals in the urine into ammonia smelling chemicals. Thus, these altered chemicals on the panties are responsible for the foul odor. Another reason can be a vegetarian diet. Many women shift to a vegetarian diet after they hit menopause. The sudden consumption of excess nitrogen-rich foods can also result in the foul odor. Urinary tract infections can also conduce to foul-smelling odor.

Prevention and Treatment
Women should consume more water during menopause. Moreover, those on a strict vegetarian diet, should consume different vegetables in the right proportion. This will help avoid the unwanted smell. In such cases, no particular treatment is required. By consuming adequate water and the right proportion of vegetables, the smell is bound to go away. However, if the condition persists do not hesitate to consult your obstetrician.
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Several women complain of a foul ammonia odor from their discharge at various stages in pregnancy.

Ammonia-smelling discharge during pregnancy can be caused by either bacterial vaginosis or concentrated urine. Bacterial vaginosis during pregnancy is quite dangerous and can lead to various pregnancy complications like preterm delivery of the baby, low birth weight issues, ectopic pregnancy, birth defects, etc. Another cause for the ammonia smell is leakage of concentrated urine. During pregnancy, the body requires adequate amounts of water intake. If the water consumed is not enough, the urine will turn out to be concentrated. Moreover, the pressure of the growing uterus on the bladder results in urine seepage. When this concentrated urine comes in contact with the underwear, bacteria act on it and a foul odor emanates. Urinary tract infections can also be the reason for this odor.

Prevention and Treatment
During pregnancy, one should ensure one drinks plenty of water and other fluids. Keeping one’s body hydrated is the key to keeping the foul smell due to concentrated urine away. Moreover, wearing a panty liner will soak the intermittent leaks and prevent the foul odor. However, make sure you change the liner frequently. In case of bacterial vaginosis and urinary tract infections, the obstetrician will prescribe the necessary treatment to get rid of this condition as soon as possible.
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Excessive Sweating

If we restricted sweat odor to our armpits and feet, we should understand that sweating down there is also a natural phenomenon.

The vulva comprises several apocrine or sweat glands and as we all know, where there are sweat glands, there is sweat and unpleasant odor. This is because the body’s waste product urea, is also excreted through the sweat. Moreover, the region also contains oil glands which produce oil. The more the oils present in the sweat, the stronger will be the vulvovaginal odor. When this odor combines with the skin bacteria and detergent from washed undergarments, a foul ammonia smell is released. Sometimes consuming a new vitamin pill can also conduce to foul-smelling vaginal odor.

Prevention and Treatment
Wearing a panty liner throughout the day is a good solution. Keep changing the liner frequently and ensure the vaginal region is always clean and dry. Wearing cotton panties is also a better option. Wash the vaginal region with antibacterial soap and try keeping the area as dry as possible. In case of excessive sweating, there exist various pills that can be prescribed. However, the medicine will reduce sweating uniformly, in all sweat glands of the body.
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Washing Panties with Bleach

While you thought rinsing your panties in bleach solution was a good idea, turns out it’s not. Using bleach while washing one’s underwear can impart an ammonia smell.

The genital area contains sweat glands that produce sweat. When this sweat combines with the bleach in the underwear, it forms an ammonia kind of smell. Often this smell is mistaken to be coming from the vaginal discharge.

Prevention and Treatment
The only way to avoid the foul odor induced by bleaching panties is avoid bleaching them. Try opting for the milder liquid detergents that not only wash the clothing clean, but also leave minimal residue on them.
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Sometimes while urinating, some women fail to empty their bladder completely. The presence of this residue urine in the bladder for a long time, results in ammonia generation. When this urine is released, a foul ammonia smell is observed. Then again, some forget to remove their tampon, which results in bacterial growth and again causes foul odor. Some sexually transmitted diseases also cause ammonia smelling urine. Often women mistake the foul smell from the discharge, while it’s actually emanating from the urine. If you want to find out for sure, try smelling the discharge alone, without the panty.

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Dr. Jimmy Obaji M.D.

Dr. Jimmy Obaji completed his residency in Family Medicine at the University of Manitoba. He currently operates a walk-in-clinic in downtown Toronto.

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