Green discharge is almost always a sign of infection. Unlike the clear or white discharge that’s a normal part of vaginal health, green-colored discharge signals that your immune system is actively fighting something off, most commonly a sexually transmitted infection like trichomoniasis or gonorrhea. The color itself comes from a specific enzyme inside white blood cells called neutrophils. When these immune cells flood an area to combat bacteria or parasites, the iron-containing enzyme they release has a vivid green pigment, the same reason pus can appear greenish. So the greener the discharge, the more intensely your body is responding to an invader.
Why Discharge Turns Green
Normal vaginal discharge changes throughout the menstrual cycle, ranging from clear and stretchy around ovulation to thicker and white in the days before a period. These variations are healthy. Green, yellow-green, or gray discharge falls outside that normal range and points to an active immune response. The green color specifically comes from an enzyme originally named “verdoperoxidase” (verde meaning green) because of its striking color. It’s packed inside neutrophils, the white blood cells your body sends first to fight infection. When enough of these cells accumulate in vaginal or urethral fluid, the discharge takes on a greenish tint.
Most Common Causes
Trichomoniasis
Trichomoniasis is one of the most common STIs worldwide and the classic cause of green or yellow-green discharge. It’s caused by a tiny parasite spread through sexual contact. In women and people with vaginas, the discharge is often frothy or bubbly, sometimes with a fishy smell. You may also notice itching, burning, redness or soreness around the genitals, and discomfort when urinating. In men, trichomoniasis can cause irritation inside the penis, burning after urination or ejaculation, and penile discharge. Many people with trichomoniasis have no symptoms at all, which makes testing important if a partner has been diagnosed.
Gonorrhea and Chlamydia
Both of these bacterial STIs can produce cloudy, yellow, or green discharge. In women, gonorrhea and chlamydia often infect the cervix, causing what’s known as cervicitis. Signs include purulent (pus-like) discharge visible at the opening of the cervix and bleeding triggered by even gentle contact. In men, these infections cause urethritis, with symptoms ranging from a mucus-like drip to thick, pus-filled discharge alongside painful urination. Many infections, especially chlamydia, produce mild or no symptoms, so people may carry and spread the infection without knowing.
Bacterial Vaginosis
Bacterial vaginosis (BV) is the most common vaginal infection in reproductive-age women, though it’s not sexually transmitted in the traditional sense. It happens when the balance of bacteria in the vagina shifts. BV typically produces a thin, white or gray discharge with a strong fishy odor, especially after sex. While BV discharge is less commonly green, it can sometimes appear grayish-green, and it’s worth considering alongside other causes. Burning during urination and itching around the vulva are also common with BV.
How These Infections Are Diagnosed
A healthcare provider will typically start by examining the discharge and asking about symptoms like odor, itching, and pain. From there, several tests can help pinpoint the cause. A vaginal pH test checks acidity levels: a pH above 4.5 suggests BV, though it can’t confirm the diagnosis on its own. A microscopy exam, where a sample of discharge is viewed under a microscope, can identify the trichomoniasis parasite, clue cells associated with BV, or white blood cells pointing to gonorrhea or chlamydia.
For STIs, nucleic acid amplification tests (essentially DNA-based tests) are the most accurate option. These can detect the genetic material of gonorrhea, chlamydia, and trichomoniasis from a swab or urine sample. At-home pH test kits exist, but they only tell you whether your vaginal acidity is off. A high pH doesn’t confirm any specific infection, and a normal pH doesn’t rule one out.
What Treatment Looks Like
All of the infections that cause green discharge are treatable, usually with a short course of antibiotics or antiparasitic medication. Trichomoniasis is treated with an oral antiparasitic. For women, the current recommended approach is a seven-day course rather than the older single-dose method, which proved less effective. Men are still typically treated with a single dose. Gonorrhea requires an antibiotic injection, sometimes paired with an oral antibiotic if chlamydia hasn’t been ruled out. BV is treated with antibiotics as well, and recent research has shown that treating male sexual partners of women with BV significantly reduces recurrence rates.
Most people feel improvement within a few days of starting treatment. It’s important to avoid sexual contact during treatment and to ensure any recent partners are also tested and treated, since reinfection is common otherwise.
Green Discharge in Men
Men searching this topic are most likely seeing discharge from the urethra (the opening at the tip of the penis). This is called urethritis, and it’s almost always caused by an STI, most often gonorrhea, chlamydia, or trichomoniasis. The discharge can range from thin and mucus-like to thick and pus-filled. Other symptoms include burning during urination, itching inside the penis, and in the case of trichomoniasis, burning after ejaculation. Any penile discharge that’s green, yellow, or cloudy warrants testing, since untreated infections can spread to the testicles or prostate and cause longer-term problems.
Risks During Pregnancy
Green or yellow discharge during pregnancy deserves prompt attention. While increased vaginal discharge is normal in pregnancy due to hormonal changes, an unusual color like green, gray, or yellow can signal an infection that needs treatment. Untreated vaginal infections during pregnancy carry risks including preterm labor and, in rare cases, infection of the amniotic sac surrounding the baby. Trichomoniasis in particular has been linked to premature birth and low birth weight. Early detection and treatment can prevent these complications, and the medications used are generally considered safe during pregnancy.
Signs That Need Urgent Attention
Green discharge on its own is reason enough to get tested, but certain additional symptoms suggest the infection may have spread beyond the vagina or urethra. Intense lower abdominal or pelvic pain, high fever, severe vomiting, or pain during sex can be signs of pelvic inflammatory disease (PID), a condition where bacteria travel from the cervix into the uterus, fallopian tubes, or ovaries. PID can cause lasting damage to reproductive organs if untreated, including scarring that leads to infertility or chronic pelvic pain. These symptoms call for same-day medical evaluation rather than waiting for a scheduled appointment.