What STI Smells Like Onions and How Is It Treated?

An unpleasant onion-like vaginal odor may be a sign of a sexually transmitted infection (STI) such as trichomoniasis or chlamydia, though it can also be caused by dietary choices or bacterial vaginosis. It is important to seek medical advice and treatment, and the infections that cause this symptom are usually treatable.

What Infections Can Give Your Vagina an Onion-Like Smell?

Not all sexually transmitted infections (STIs) cause vaginal odor, and many may not show any symptoms at all. This is why practicing safe sex is crucial. Here are the two STIs most often linked to an onion-like vaginal odor.

Trichomoniasis

Trichomoniasis, or trich, is a treatable sexually transmitted infection that can cause an unpleasant onion-like odor. Other symptoms include itching or discomfort during sex and discharge, which may be yellow or green.

Only about 30% of people with trich experience symptoms, so you can unknowingly carry and transmit the infection to your partners.

Chlamydia

Chlamydia is a common, treatable STI. This bacterial infection appears on various parts of the body, including the vagina, penis, rectum, or throat.

Chlamydia often has no symptoms. When they do occur, unusual vaginal odor is common, and there may also be discharge, swelling, and pain with urination.

What Else Could Cause an Onion Smell?

A strong onion-like odor may not always indicate an STI. It could be due to factors like body odor, diet, or a forgotten tampon. Some possible causes include:

• Poor hygiene: Excess discharge or improper cleaning after urination
• Food: Consuming lots of foods in the allium family, like onions, garlic, and shallots
• Hormonal changes: Periods, pregnancy, and menopause
• Forgotten tampon: Results in bacterial growth
• Bacterial vaginosis: An imbalance in bacteria in the vagina
• Rectovaginal fistula: An uncommon internal connection between the rectum and vagina
• Cervical or vaginal cancer: May be accompanied by discharge, pain, and abnormal bleeding

How Is Unusual Vaginal Odor Diagnosed and Treated?

If you notice a strong, unusual vaginal odor, it’s important to get tested for STIs. A healthcare provider may review your medical and sexual history and may perform tests such as blood tests, vaginal swabs, urine tests, or a vaginal exam to determine the odor’s cause.

Luckliy, most STIs that cause an onion-like vaginal odor are easily treatable. Completing a full course of medication can clear most infections in one to two weeks. If the odor is due to lifestyle factors or other conditions, your healthcare provider will recommend suitable treatments. You may also be advised to avoid sexual activity until the odor resolves.

Tips to Keep Vaginal Odors at Bay

Vaginas are self-regulating and can usually rebalance bacteria and pH (acidity) levels on their own. But some people are more sensitive or prone to vaginal imbalances. At-home practices can help your vagina stay healthy and have a typical odor. Consider implementing the following prevention methods:

• Practice safer sex, including allergen-free barrier methods that work for you and your partner.
• Get regular STI screenings.
• Avoid sex when symptoms are present.
• Eat a diet rich in fresh fruits and vegetables.
• Drink lots of water throughout the day.
• Exercise regularly and quickly change out of sweaty gym clothes.
• Try pelvic floor exercises.
• Use mild soap and lukewarm water to clean around the vulva (exterior genitalia).
• Wear loose clothes and cotton underwear.
• Consume probiotics through food such as yogurt or kimchi or via supplements.

When to Contact a Healthcare Provider

It’s important to seek professional medical care for any abnormal vaginal odors, especially when other symptoms accompany them. Left untreated, STIs can cause complications with pregnancy, spread to different areas of the reproductive system, or continue to get transmitted to sexual partners.

Seek help if you’re experiencing:

• Fever
• Unusual discharge
• Foul odor
• Pain or burning
• Bumps, marks, or ulcers