Green vaginal discharge is not normal and typically signals an infection that needs treatment. The most common causes are sexually transmitted infections like trichomoniasis and gonorrhea, though bacterial vaginosis, a forgotten tampon, or a complication called pelvic inflammatory disease can also be responsible.
The green color itself has a straightforward biological explanation. When your body fights an infection, it sends large numbers of white blood cells called neutrophils to the site. These cells contain an enzyme that was originally named “verdeperoxidase” because of its vivid green pigment. When enough of these cells accumulate in vaginal fluid, they tint the discharge green, much the same way infected mucus turns green during a sinus infection.
Trichomoniasis: The Most Common Cause
Trichomoniasis is the single most likely reason for green discharge. It’s caused by a tiny parasite, and roughly 2 million people in the U.S. are diagnosed with it each year. The discharge it produces tends to be thin and foamy with a strong fishy smell, though it can also appear yellow or white. Other signs include itching or burning around the genitals, discomfort during urination, and pain during sex.
Many people with trichomoniasis have mild or no symptoms at all, which means it often goes undiagnosed and gets passed to partners unknowingly. A standard course of oral antibiotics taken twice daily for seven days clears the infection in most cases. Your sexual partners need treatment too, even if they have no symptoms, because reinfection is common. Partners from the previous 60 days should ideally be treated or evaluated.
Gonorrhea and Chlamydia
Gonorrhea can produce a thick green or yellow discharge that’s heavier than what you’d normally expect. You might also notice painful urination and bleeding between periods. Chlamydia causes similar symptoms, though it more commonly produces yellow discharge and frequently causes no noticeable symptoms at all. Both infections are bacterial and treatable with antibiotics.
What makes these two infections particularly important to catch early is what happens when they’re left untreated. Gonorrhea and chlamydia are the leading causes of pelvic inflammatory disease, an infection that spreads into the uterus, fallopian tubes, or ovaries. PID can cause chronic pelvic pain and permanent damage that leads to infertility. Gonorrhea left unchecked can also spread to the bloodstream, potentially causing joint infections and skin problems.
Bacterial Vaginosis
Bacterial vaginosis (BV) isn’t sexually transmitted. It happens when the natural balance of bacteria in the vagina shifts, allowing certain types to overgrow. The discharge is often grayish-white but can take on a green or yellow tint, particularly when the overgrowth triggers a stronger immune response. A fishy odor, especially after sex, is the hallmark symptom.
BV is treated with antibiotics and tends to resolve quickly, but it has a frustrating tendency to come back. Maintaining a healthy vaginal pH is part of prevention. A normal vaginal pH sits around 4.2 to 4.5, though this varies somewhat by ethnicity. Both BV and trichomoniasis push the pH above 4.5, which is one reason testing can help distinguish between different causes of abnormal discharge.
Foreign Objects
A forgotten tampon, a piece of a condom, or another object left in the vagina will eventually cause an infection as bacteria multiply around it. The resulting discharge is usually greenish-yellow, brown, or pink and has a distinctly foul smell that’s hard to miss. Removal of the object often resolves the problem quickly, though antibiotics may be needed if infection has set in.
Green Discharge During Pregnancy
If you’re pregnant, green discharge deserves prompt attention. Vaginal infections during pregnancy can trigger the release of compounds that stimulate uterine contractions, raising the risk of premature labor. Bacterial vaginosis specifically has been linked to increased rates of premature rupture of membranes, spontaneous miscarriage, infection of the amniotic fluid, and postpartum complications like uterine infections.
Preterm delivery carries significant risks for the baby, so treating the underlying infection early matters. The good news is that most causes of green discharge can be safely treated during pregnancy.
Signs the Infection May Be Spreading
Green discharge on its own warrants testing, but certain additional symptoms suggest the infection may have moved beyond the vagina into the reproductive organs. Watch for lower abdominal pain, fever, pain or bleeding during sex, and burning urination. These are the classic signs of pelvic inflammatory disease. PID symptoms can be surprisingly mild, so even low-grade pelvic discomfort alongside abnormal discharge is worth getting evaluated.
PID is treatable with antibiotics, but any scarring it causes in the fallopian tubes is permanent. Early treatment makes a significant difference in long-term outcomes, particularly for fertility.
What Testing Looks Like
Diagnosing the cause of green discharge is usually straightforward. A healthcare provider will take a swab of the discharge and may also collect a urine sample. These samples can be tested for trichomoniasis, gonorrhea, and chlamydia, often with results available within a day or two. BV is typically diagnosed by examining the discharge under a microscope and checking the vaginal pH.
Because STIs frequently occur together, testing for multiple infections at once is standard. You should also expect to be offered an HIV test, since having one STI increases vulnerability to others. If you’re diagnosed with chlamydia or gonorrhea, your sexual partners from the past 60 days need to be notified and treated. In many states, your provider can give you a prescription or medication to pass along to a partner who can’t get to a clinic quickly.