Vaginal yeast is a fungus called Candida that naturally lives on the vaginal lining in small amounts. It’s part of the normal microbial community and usually causes no problems. But when conditions shift in the vagina, Candida can multiply beyond its usual numbers, causing what’s commonly called a yeast infection (clinically known as vulvovaginal candidiasis). About three out of four women will have at least one yeast infection in their lifetime, and roughly 10% of those will deal with recurring episodes.
How Yeast Lives in the Vagina Normally
Your vagina hosts a whole ecosystem of microorganisms, including bacteria and small amounts of yeast. In a healthy state, beneficial bacteria (especially certain Lactobacillus species) keep yeast populations in check by maintaining an acidic environment, typically between a pH of 3.8 and 4.5. This acidity makes it hard for Candida to grow aggressively. The yeast stays in a round, inactive form, coexisting peacefully with the rest of the vaginal flora.
Problems start when something disrupts that balance. When Lactobacillus populations drop or the vaginal environment changes, Candida can shift from its harmless round shape into elongated, branching filaments that actively invade tissue. This shape change is one of the fungus’s key tricks: the filaments can burrow into the vaginal lining and produce a toxin called candidalysin that damages cells and triggers inflammation. That inflammation is what produces the symptoms you feel.
What Triggers an Overgrowth
Several common factors can tip the balance in Candida’s favor:
- Antibiotics. Broad-spectrum antibiotics kill off protective Lactobacillus along with the bacteria they’re targeting, giving yeast room to expand.
- Higher estrogen levels. Pregnancy, birth control pills, and hormone therapy all raise estrogen, which promotes yeast growth. This is why yeast infections are more common during pregnancy.
- Diabetes. Elevated blood sugar creates a more favorable environment for Candida to feed and multiply.
- Weakened immune function. Anything that suppresses the immune system, from illness to medications, can reduce the body’s ability to keep yeast in check.
- Shifts in vaginal bacteria. A decline in protective Lactobacillus species, particularly when replaced by less beneficial strains, can leave the vagina more vulnerable to yeast overgrowth.
What a Yeast Infection Looks and Feels Like
The hallmark symptom is a thick, white discharge that’s often described as looking like cottage cheese. It can also be watery. Unlike some other vaginal infections, yeast infections typically have little to no odor.
Beyond the discharge, most women notice intense itching and irritation around the vulva and vaginal opening. Burning during urination is common, as is discomfort or pain during sex. The skin around the vulva may appear red and swollen. Symptoms can range from mild to severe, and they sometimes worsen in the days leading up to a period.
Yeast Infection vs. Bacterial Vaginosis
These two conditions are easy to confuse because both involve changes in vaginal discharge, but they look and smell quite different. With bacterial vaginosis (BV), the discharge tends to be thin, grayish, and heavier in volume, with a noticeable fishy odor that’s especially strong after a period or after sex. With a yeast infection, the discharge is thick, white, and largely odorless. BV is caused by an overgrowth of bacteria, not yeast, and the two require different treatments. If you’re unsure which one you’re dealing with, getting the right diagnosis matters because treating the wrong condition won’t resolve your symptoms.
How Yeast Infections Are Treated
Most uncomplicated yeast infections clear up with antifungal medication, available both over the counter and by prescription. Over-the-counter options come as creams, ointments, or suppositories that you insert vaginally, usually for one to seven days depending on the product. Single-dose oral antifungal tablets are also widely used and work from the inside.
For a first-time infection, many women find relief within a few days of starting treatment, though it’s worth finishing the full course even if symptoms improve quickly. Recurring infections, defined as four or more episodes per year, affect up to 9% of women who get yeast infections and often require a longer or maintenance treatment plan.
Reducing Your Risk
Because yeast thrives in warm, moist environments, a few practical habits can help keep things balanced. Wearing breathable cotton underwear and avoiding sitting in wet clothing (like swimsuits or sweaty workout gear) reduces moisture buildup. Avoiding douches and scented vaginal products helps preserve the natural bacterial balance that keeps yeast in check.
There’s growing evidence that oral probiotics containing Lactobacillus strains can support vaginal health. One clinical study found that women who took a daily probiotic blend for six weeks saw measurable increases in vaginal Lactobacillus populations, and 60% of those with disrupted vaginal flora showed improvement. These results are promising, though probiotics work best as a supporting strategy alongside other preventive habits, not as a standalone fix during an active infection.
If you’re prone to yeast infections around antibiotic use, letting your prescribing provider know can be helpful. Some women benefit from a preventive antifungal course alongside their antibiotics.