Why Does Period Blood Smell Like Fish? Understanding Menstrual Odors


For many people with periods, it’s not uncommon to experience a unique odor during their menstrual cycle. One particularly pungent smell that some individuals might notice is a fishy odor. In this article, we’ll explore why period blood might sometimes smell like fish. We’ll cover the science behind menstrual odors, possible reasons why you might be experiencing this type of odor, and what you can do to manage or eliminate it. We’ll also discuss the importance of understanding vaginal health and breaking the stigma around menstrual odors.

The Science Behind Why Period Blood Can Smell Like Fish

Vaginal health is a delicate balance of bacteria and other microorganisms. These microorganisms are necessary to maintain a healthy pH balance and prevent infections. However, when there is a disruption in this balance, it can lead to unpleasant odors and other issues.

During menstruation, the vaginal pH balance can be thrown off by menstrual blood. Blood has a pH of around 7.4, which is slightly basic. On the other hand, the vagina normally has a slightly acidic pH of 3.8 to 4.5. This acidic environment is necessary for maintaining healthy bacteria and preventing infections. The introduction of menstrual blood can temporarily raise the pH, leading to an increase in odor-causing bacteria.

One specific type of bacteria that can cause a fishy odor is called Gardnerella vaginalis. This bacteria is responsible for a condition called bacterial vaginosis (BV), which we’ll discuss in more detail later on.

5 Possible Reasons Why Your Menstrual Blood Smells Fishy

Here are five common reasons why your menstrual blood might smell fishy:

Bacterial Vaginosis

Bacterial vaginosis (BV) is a common vaginal infection that occurs when the normal bacterial balance in the vagina is disrupted. Symptoms of BV can include a fishy odor, itching, burning, and abnormal discharge. It’s important to seek medical treatment if you suspect you have BV, as it can increase your risk of other infections and complications.

Poor Menstrual Hygiene

It’s important to practice good hygiene during your period to prevent odor and infection. This includes changing your pads or tampons regularly, washing your genitals daily with mild soap and water, and avoiding scented products that could irritate the vagina.

Medications or Supplements

Certain medications and supplements can affect the pH balance of the vagina and lead to odors. Antibiotics, for example, can disrupt the balance of bacteria and increase the risk of BV. Taking vitamin supplements with high levels of vitamin B6 or zinc can also lead to a fishy odor.

Certain Foods or Drinks

What you eat and drink can also affect vaginal odor. Foods that are high in sulfur, such as garlic and onions, can lead to a strong odor. Alcohol and caffeine can also affect the pH balance and increase the risk of odors.


Some sexually transmitted infections (STIs) can cause a fishy odor. Trichomoniasis, for instance, is a common STI that can cause itching, burning, and a strong odor. It’s important to get tested regularly for STIs and to practice safe sex to prevent infection.

What to Do If You Notice a Fishy Odor During Your Period

If you’re experiencing a fishy odor during your period, there are several things you can do to manage or eliminate it:

Practicing Good Hygiene

As we mentioned earlier, practicing good hygiene is key to preventing odors and infections. Make sure to change your pads or tampons regularly, wash your genitals daily with mild soap and water, and avoid scented products that can irritate the vagina.

Using Unscented Menstrual Products

Scented menstrual products can irritate the vagina and make odors worse. Opt for unscented pads or tampons, and consider using a menstrual cup or period panties, which are made with breathable materials that can help prevent odors.

Treating Infections or Underlying Health Issues

If you suspect you may have an infection or underlying health issue, it’s important to seek medical treatment. Your healthcare provider can diagnose and treat conditions like BV, STIs, and other vaginal infections.

Avoiding Certain Foods or Drinks

If you notice that certain foods or drinks are causing a strong odor, try cutting back and see if that helps. Alcohol and caffeine are common culprits, as are foods that are high in sulfur.

If your fishy odor persists despite these measures, it’s important to seek medical advice.

Understanding Vaginal Health: An Exploration of Menstrual Odors

It’s important to note that some amount of vaginal odor is normal. Every person is different, and there isn’t a single “normal” odor that applies to everyone. However, if you notice a change in your usual odor, it’s important to pay attention and seek medical help if necessary.

In addition to fishy odors, there are several other types of menstrual odors that you might notice:

Metallic Odor

Some people might notice a metallic odor during their period, which can be caused by blood. This is generally considered normal and nothing to worry about.

Sour or Vinegar-Like Odor

A sour or vinegar-like odor can indicate a yeast infection or other type of vaginal infection. It’s important to seek medical treatment if you suspect an infection.

Rotten or Decomposed Odor

A rotten or decomposed odor can indicate more serious health issues, such as a tampon that’s been left in for too long, or even cervical or endometrial cancer. If you notice this type of odor, seek medical attention immediately.

Breaking the Stigma: Let’s Talk About Why Period Blood Sometimes Smells Like Fish

Unfortunately, there is still a lot of stigma surrounding menstrual health, including menstrual odors. Some individuals might feel ashamed or embarrassed if they notice an unusual odor. However, it’s important to remember that these odors are often a normal part of menstrual cycles, and seeking medical help is nothing to be ashamed of.

It’s important to have open and honest conversations about menstrual health, including menstrual odors. Encouraging education and awareness can help break down the stigma and empower individuals to take control of their vaginal health.


In summary, a fishy odor during your period can be caused by a disruption in the vaginal pH balance, bacterial vaginosis, poor menstrual hygiene, certain medications or supplements, certain foods or drinks, and STIs. If you notice this type of odor, it’s important to practice good hygiene, use unscented menstrual products, seek medical treatment if necessary, and pay attention to any other changes in your usual odor. Remember to prioritize your vaginal health and break the stigma around menstrual odors.

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