Trimo-San Side Effects: What to Expect and When to Call Your Doctor

Trimo-San is a vaginal gel used to maintain vaginal pH and prevent odor-causing bacteria, particularly for women who use a vaginal pessary. Most patients tolerate it well — the manufacturer's labeling notes that reaction or irritation is very rare. But as with any medication, side effects can occur, and there are important signs that should prompt a call to your provider.

This guide covers what you may experience when using Trimo-San, which symptoms are expected to resolve on their own, and which symptoms require medical attention.

Is Trimo-San Generally Safe?

Trimo-San has a long history of use in pessary patients, and most users do not experience significant side effects. The two active ingredients — oxyquinoline sulfate and sodium lauryl sulfate — are present in very small concentrations (0.025% and 0.01% respectively). The product is applied topically to the vaginal walls and is not intended to be absorbed systemically, which limits the risk of systemic side effects.

That said, it is important to note that Trimo-San is not FDA-approved, and its formal safety and efficacy have not been evaluated by the FDA.

Common Side Effects of Trimo-San

The following mild side effects may occur with Trimo-San use. These may get better as your body adjusts to the medication. Let your provider know if they persist or worsen:

• Mild vaginal burning or stinging upon application
• Mild vaginal itching
• Mild vaginal discharge or wetness (due to the gel base)

The gel may leak out of the vagina during the day. Wearing a thin panty liner is helpful. Do not use a tampon to manage this leakage.

Serious Side Effects: When to Stop Using Trimo-San and Call Your Doctor

Stop using Trimo-San and contact your healthcare provider right away if you experience any of the following:

• Severe vaginal irritation, burning, or stinging that is worse than before using the medication
• Unusual or worsening vaginal discharge with bad odor
• Fever
• Pelvic pain, cramps, or lower abdominal pain

These symptoms may indicate that the medication is causing an allergic or adverse reaction — or that there is an underlying vaginal or pelvic infection that needs separate treatment.

Signs of a Serious Allergic Reaction — Seek Emergency Care

Although rare, allergic reactions to Trimo-San can occur. Seek emergency medical attention immediately if you develop:

• Hives or skin rash
• Swelling of the face, lips, tongue, or throat
• Difficulty breathing
• Rapid heartbeat or dizziness

Contact Allergies to Trimo-San Ingredients

Some patients may develop contact allergies to oxyquinoline, sodium lauryl sulfate, or the inactive ingredients in Trimo-San (which include methylparaben and perfume). Contact allergy symptoms include local itching, swelling, and rash at the site of application. If you suspect a contact allergy, discontinue use and tell your provider.

Trimo-San Warnings and Precautions

• Pregnancy: Trimo-San has not been tested during pregnancy. CooperSurgical does not recommend its use during pregnancy. Tell your provider if you are or may be pregnant.
• Conception: Do not use Trimo-San within 6 hours before or after intercourse if you are trying to become pregnant. The product may interfere with conception.
• Breastfeeding: It is not known whether hydroxyquinoline passes into breast milk. Tell your provider if you are breastfeeding before using Trimo-San.
• Pessary compatibility: Trimo-San is compatible with Milex pessaries. Check with your provider before using it with other pessary types, as some materials may interact with the gel's ingredients.

Reporting Side Effects

You can report side effects from Trimo-San to the FDA at 1-800-FDA-1088. Any unusual or persistent symptoms should be shared with your healthcare provider. For more information about Trimo-San uses and dosing, see our guide: What Is Trimo-San? Uses, Dosage, and What You Need to Know in 2026.