Green discharge is a sign that your body is actively fighting an infection. The green color comes from a specific enzyme inside neutrophils, the white blood cells your immune system sends to destroy invading bacteria or parasites. When large numbers of these cells flood an area, the enzyme’s natural pigment turns the surrounding fluid green. The most common causes are sexually transmitted infections like trichomoniasis, gonorrhea, and chlamydia, though other conditions can be responsible too.
Why Discharge Turns Green
The green tint isn’t random. Neutrophils, a type of white blood cell, contain an enzyme that was originally named “verdeperoxidase” because of its vivid green color. When your body detects an infection in the vaginal canal, cervix, or urethra, it floods the area with these cells. As they accumulate in mucus or pus, the discharge shifts from clear or white to yellow-green or bright green. The more intense the immune response, the more vivid the color tends to be.
This is the same reason wound infections produce greenish pus. The color itself isn’t harmful. It’s a visible marker that your immune system is engaged in a fight, and it tells you something needs medical attention.
Trichomoniasis
Trichomoniasis is one of the most recognizable causes of green discharge. It’s caused by a parasite spread through sexual contact, and it produces discharge that is often yellow-green, frothy or bubbly in texture, and accompanied by a fishy smell. You may also notice itching, burning during urination, and vulvar irritation.
Trichomoniasis shifts vaginal pH significantly. A healthy vagina typically sits between 4.0 and 4.5 on the pH scale, but trichomoniasis can push it above 5.4, sometimes as high as 6.5. That alkaline shift disrupts the normal bacterial balance and contributes to the strong odor many people notice. Treatment is a course of oral antibiotics, typically taken twice daily for seven days for women. Men are usually treated with a single dose. Sexual partners need treatment at the same time, or reinfection is almost guaranteed.
Gonorrhea and Chlamydia
Both gonorrhea and chlamydia can cause cloudy, yellow, or green discharge. In women, gonorrhea often shows up as increased vaginal discharge alongside burning with urination, bleeding between periods, or pelvic pain. In men, it typically appears as a white, yellow, or green discharge from the penis, often with painful urination.
Chlamydia is trickier because it frequently causes no symptoms at all, especially in women. When it does produce discharge, the color can range from cloudy white to yellowish-green. Both infections can also affect the rectum, causing discharge from that area as well. Left untreated, either infection can lead to pelvic inflammatory disease, which can cause chronic pain and fertility problems.
Bacterial Vaginosis
Bacterial vaginosis is the most common vaginal infection in women of reproductive age, and while its classic presentation is a thin, grayish-white discharge with a strong fishy odor, it can sometimes appear yellowish or off-color. It results from an overgrowth of certain bacteria that upset the vaginal environment, pushing the pH above 4.5. Burning, itching, and a smell that intensifies after sex are common complaints. BV is not sexually transmitted, but sexual activity can trigger it.
Forgotten Tampons and Foreign Objects
A retained tampon or other foreign object in the vagina can produce foul-smelling, discolored discharge that ranges from dark brown to greenish. The object creates a breeding ground for bacteria, and the immune response follows. The key clue is often the smell, which tends to be extremely strong and distinct from infection-related odors. Pelvic pain and discharge that doesn’t respond to antibiotics should raise suspicion for a retained object. In rare cases, a forgotten tampon can lead to toxic shock syndrome, which causes fever, rash, and dangerously low blood pressure.
Green Discharge During Pregnancy
Any infection that causes green discharge is more concerning during pregnancy. Research has linked pathological vaginal discharge in pregnant women to significantly higher rates of premature membrane rupture and preterm delivery. Trichomoniasis in particular is associated with premature rupture of membranes, preterm labor, and low birth weight. Bacterial vaginosis carries similar risks, including postpartum uterine infections. These aren’t theoretical dangers: studies have found statistically significant increases in both complications among pregnant women with abnormal discharge compared to those without.
How Infections Are Identified
Discharge color alone can’t tell you which infection you have. Several conditions overlap in appearance, so testing matters. The traditional approach involves looking at a sample under a microscope, but this method misses a lot. Microscopy catches only about 75% of trichomoniasis cases and less than half of yeast infections. Newer molecular tests that detect genetic material from the infectious organism are far more accurate, identifying trichomoniasis in virtually 100% of cases and yeast infections about 92% of the time.
If you’ve been tested with a basic microscope exam and told everything looks normal, but your symptoms persist, it’s worth asking about molecular testing. A negative result on microscopy doesn’t rule out infection.
What to Expect From Treatment
Most infections that cause green discharge are treated with oral antibiotics or antiparasitics. Trichomoniasis and bacterial vaginosis both respond to the same class of medication. Gonorrhea and chlamydia each require different antibiotics, and they’re sometimes treated simultaneously since the two infections frequently occur together.
You should avoid sexual contact during treatment and until symptoms fully resolve. Sexual partners need to be treated as well for any STI, even if they have no symptoms. Retesting after treatment is recommended for trichomoniasis, since reinfection rates are high. Most people notice their discharge returning to normal within a week or two of starting the correct treatment, though it can take slightly longer for irritation and odor to fully clear.