Green vaginal discharge is almost always a sign of infection. Normal discharge ranges from clear to white, so a green or yellow-green color typically means your body is fighting off bacteria or a parasite. The most common cause is trichomoniasis, a sexually transmitted infection, but other infections and even a forgotten tampon can be responsible.
Trichomoniasis: The Most Common Cause
Trichomoniasis is a sexually transmitted infection caused by a tiny parasite. It’s one of the most curable STIs, but it often goes undiagnosed because many people have no symptoms at all. When symptoms do appear, green discharge is one of the hallmarks. The CDC describes it as a clear, white, yellowish, or greenish discharge that tends to be thin or higher in volume than usual, often with a noticeable fishy smell.
Beyond the discharge itself, trichomoniasis can cause itching, burning, redness around the genitals, and discomfort during urination or sex. Symptoms can come and go, which sometimes leads people to assume the problem resolved on its own. It doesn’t. Without treatment, the infection persists and can be passed to sexual partners. A standard course of oral antibiotics taken twice daily for seven days clears most cases, though reinfection is common if your partner isn’t treated at the same time.
Gonorrhea and Chlamydia
Both gonorrhea and chlamydia can produce abnormal discharge, though the color is more often yellow than distinctly green. Gonorrhea is the second most common STI in the United States, and chlamydia is the first. The tricky part is that both infections frequently cause no symptoms at all, especially in the early stages. When discharge does appear, it may look yellow or simply different from what you’re used to.
Left untreated, either infection can spread to the uterus and fallopian tubes, leading to pelvic inflammatory disease. PID can cause intense lower belly pain, fever, severe vomiting, and foul-smelling discharge. It can also lead to long-term complications like chronic pelvic pain and fertility problems. If you notice unusual discharge along with pelvic pain or fever, that combination warrants prompt medical attention.
Desquamative Inflammatory Vaginitis
Not every cause of green discharge is an STI. Desquamative inflammatory vaginitis (DIV) is a non-infectious condition where the vaginal lining becomes chronically inflamed. The most common symptom is an increase in vaginal discharge that appears yellowish-green. DIV can also cause soreness, burning, and discomfort during sex.
The exact cause of DIV isn’t fully understood, but it’s thought to involve a disruption in the normal balance of vaginal bacteria combined with an inflammatory response. It’s less well-known than conditions like yeast infections or bacterial vaginosis, which means it sometimes goes undiagnosed for months. Treatment typically involves prescription medication to calm the inflammation and restore the vaginal environment.
Bacterial Vaginosis
Bacterial vaginosis happens when the balance of bacteria in the vagina shifts, with normally dominant protective bacteria being outnumbered by other types. The classic presentation is a thin, white or gray discharge with a fishy odor. BV doesn’t typically produce green discharge on its own, but the color can sometimes shift toward grayish-green, especially if BV occurs alongside another infection. If your discharge is distinctly green, BV alone is unlikely to be the explanation, and your doctor will probably test for other causes as well.
A Retained Tampon or Foreign Object
A forgotten tampon is a surprisingly common cause of foul-smelling, discolored discharge. The discharge can be yellow, green, pink, gray, or brown, and the smell is often the first thing people notice. It tends to be strong and unmistakable. This can happen more easily than you’d think: inserting a second tampon without removing the first, or simply losing track during a busy day. Removing the object usually resolves the discharge within a day or two, though if you can’t reach it yourself, a healthcare provider can remove it quickly.
Green Discharge During Pregnancy
Pregnancy increases vaginal discharge in general, which is normal. But green, gray, or yellow discharge during pregnancy is not normal and can signal an infection that needs treatment. This matters more during pregnancy because certain vaginal infections are linked to complications like preterm labor or infection of the amniotic sac. Trichomoniasis, in particular, has been associated with premature delivery and low birth weight. If you’re pregnant and notice green or unusually colored discharge, getting tested promptly helps protect both you and the pregnancy.
How Doctors Identify the Cause
Figuring out what’s behind green discharge usually starts with a sample of the discharge itself. Your provider collects a swab and examines it under a microscope. Different infections leave distinct fingerprints. Trichomoniasis shows up as tiny moving parasites on the slide, along with a high number of white blood cells, which signals active inflammation. Bacterial vaginosis reveals “clue cells,” which are vaginal cells coated with bacteria, along with a noticeable lack of the healthy bacteria that normally dominate. Yeast infections show branching fungal structures. The microscope exam catches trichomoniasis about 60% of the time, so if the initial test is negative but suspicion remains, your provider may send a more sensitive lab test.
Your provider will also check the vaginal pH. A healthy vagina is slightly acidic, with a pH below 4.5. Trichomoniasis and bacterial vaginosis both push the pH higher. A fishy odor that gets stronger when a chemical solution is added to the sample is another classic sign of BV or trichomoniasis. STI testing for gonorrhea and chlamydia is typically done through a urine sample or cervical swab and run separately from the microscope exam.
What to Pay Attention To
Green discharge on its own is reason enough to get checked. But certain combinations of symptoms suggest a more urgent situation. Intense lower abdominal pain paired with discolored or smelly discharge can indicate pelvic inflammatory disease, which needs treatment quickly to prevent lasting damage. A high fever, severe vomiting, or rapidly worsening pain all fall into the same category. Even without those red flags, discharge that’s persistently green, has a strong odor, or comes with itching or burning is worth a visit. Most causes are straightforward to diagnose and respond well to treatment, especially when caught early.