How to Get Period Blood Out of Pants and Underwear

Wondering how to get period blood out of pants, underwear, or period underwear? Most period blood stains come out completely if you act within the first few minutes and always start with cold water. In this guide, we cover the four proven removal methods, from fresh stains to fully dried ones, and explain exactly what works on cotton, denim, leggings, bedding, and period underwear (also called period pants). 

Table of Contents:

1. Why period blood stains so easily
2. The four stain removal methods — and when to use each
3. Method 1: The cold water flush (fresh stains)
4. Method 2: The salt paste method (1–2 hours old)
5. Method 3: The baking soda soak (dried/set stains)
6. Method 4: The hydrogen peroxide method (light fabrics)
7. Fabric-specific guide: cotton, denim, leggings, bedding, car seats & period underwear
8. Common mistakes that permanently set stains
9. Frequently asked questions
   

Why period blood stains so easily

Period blood stains are protein-based, which means heat, including hot water, tumble drying, or ironing, permanently bonds the proteins (primarily haemoglobin) to fabric fibres. Once those proteins bind permanently to fibres, even the best stain remover can only fade the mark, not remove it.

That's why the first few minutes after a leak matter more than any product you buy.

If you can't deal with it immediately — you're at work, at school, or travelling — blot the stain gently with cold wet tissue to remove as much blood as possible, and avoid rubbing it in further. Treat it properly with cold water as soon as you get home. The stain will be harder to remove once dry, but it's rarely permanent.

The Four Methods — and When to Use Each

Best practice: Always start with cold water before using any of these methods.

Method 1: The Cold Water Flush Method (Fresh Stains)

For most fresh period stains, this is the only step you need.

1. Remove the garment and take it to a cold tap immediately.
2. Hold the stained area so cold water runs through the back of the fabric. This pushes the blood out rather than deeper in.
3. Flush for 1–2 minutes. Most fresh stains disappear at this stage alone.
4. Rub a small amount of bar soap or unscented washing-up liquid into the damp stain.
5. Work the soap in gently with your fingers. Don't scrub, as that pushes blood deeper into the fibres.
6. Rinse again under cold water until the water runs clear.
7. If a faint mark remains, soak in cold water with a teaspoon of table salt for 30 minutes, then rinse and air-dry.

Don't: use warm or hot water, put it in the tumble dryer, or iron over the stain at any stage.

Method 2: The salt paste method (stains up to 2 hours old)

Salt helps lift blood from fabric before it fully sets and binds to fibres. It works especially well on cotton underwear and bed sheets.

1. Mix table salt with cold water until you have a thick paste — roughly 2 parts salt to 1 part water.
2. Spread the paste over the entire stain, pressing it gently into the fabric.
3. Leave for 30 minutes for recent stains, up to 2 hours for older ones.
4. Rinse thoroughly under cold running water.
5. Follow with a normal machine wash on a cold or 30°C cycle.

Method 3: The baking soda soak method (dried or set-in stains)

Dried period blood stains are harder to remove, especially if they've been through a warm wash or the dryer, but they are not always permanent.

1. Fill a basin with cold water and add 2 tablespoons of baking soda (bicarbonate of soda). Submerge the garment and soak overnight.
2. Remove the garment and make a thick paste of baking soda and a few drops of cold water.
3. Apply the paste directly to the stain and leave for 30 minutes.
4. Gently work the paste into the fabric using an old toothbrush with light circular motions.
5. Rinse with cold water and check the stain before washing.
6. If the stain remains, repeat once or follow with the hydrogen peroxide method (light fabrics only).
7. Wash on a cold cycle and air-dry. Check the stain is gone before applying any heat.

Method 4: The hydrogen peroxide method (light fabrics, set stains)

Hydrogen peroxide breaks down blood proteins through oxidation. It's effective on set stains but can lighten or strip dye from dark or coloured fabrics.

Always test on an inconspicuous area first.

1. Buy 3% hydrogen peroxide from a pharmacy (the standard over-the-counter concentration).
2. Apply a small amount directly to the stain using a clean cloth or cotton bud.
3. Watch for gentle fizzing — this is the peroxide reacting with the blood proteins.
4. Leave for 5–10 minutes.
5. Rinse thoroughly with cold water.
6. Machine wash on a cold or 30°C cycle and air-dry.
7. Do not use on dark jeans, black underwear, or any fabric where colour loss would be visible. For those, stick to the baking soda soak.

Fabric-Specific Period Stain Removal Guide

Cotton Underwear

Cotton is the most forgiving fabric for period stain removal. The “cold water flush” followed by the “salt paste” method removes most fresh period blood stains completely. For dried stains, the baking soda soak works well. Avoid hot washes and tumble drying.

Denim Jeans

Rinse the stain immediately with cold water, then soak the jeans in cold water for several hours if the stain is already setting. Avoid scrubbing: Aggressive friction damages denim fibres and spreads the stain. If a mark remains after soaking, apply hydrogen peroxide to the inside of the fabric only, as it can lighten the outer dye. Air-dry flat.

Leggings and Activewear

Most leggings are made from synthetic fibres (polyester, nylon, spandex blends) that don't  respond well to baking soda or salt. For leggings:

1. Rinse immediately under cold water from the back of the stain.
2. Apply a small amount of liquid laundry detergent or dish soap — enzyme-based formulas work especially well on protein stains.
3. Leave for 10–15 minutes, then rinse and machine wash on a cold, delicate cycle.

Avoid: fabric softener (reduces stretch), hot water, tumble drying. Hang to dry.

Bedding and Sheets (How to get period blood out of sheets)

Strip the bed immediately and take the sheet to a cold tap. Rinse the stained area, apply the salt paste or baking soda soak method, and wash on a cold cycle. White cotton sheets can tolerate a small amount of diluted hydrogen peroxide directly on the stain. Avoid bleach: It removes colour but not the blood proteins, often leaving a yellow residue.

Car Seats and Upholstery

Do not pour water over a car seat or mattress — excess moisture can cause mould. Instead:

1. Blot (don't rub) as much blood as possible with a clean cold cloth.
2. Make a baking soda paste and apply it directly to the stain.
3. Leave to dry completely, then brush or vacuum away.
4. Blot any remaining mark with a cold damp cloth and allow to air-dry thoroughly.
5. For leather seats, use cold water only and dry immediately — baking soda can damage leather finishes.

Period Underwear / Period Pants

If you frequently get period blood stains on your clothes or bedsheets, it may be a sign that your current period protection isn’t giving you enough coverage — especially overnight, on heavy-flow days, or during long days out.

That’s where period underwear can help.

Unlike regular underwear, period pants are specifically designed to absorb menstrual blood and help prevent leaks before they reach your clothes, jeans, bedding, or car seats.

Depending on the absorbency level, many people wear period underwear:

• on its own instead of pads or tampons,
• as backup protection with menstrual cups or tampons,
• overnight,
• while travelling,
• or during heavier flow days.

Modern period underwear is also designed to release blood more easily during washing, which means it generally cleans far more easily than standard cotton underwear after a leak.

For backup protection, styles like Ruby Cup’s Fearless period pants are designed to provide extra security while still feeling like regular underwear. For heavier flow days or overnight protection, more absorbent styles like Flow Freedom period pants can be worn on their own or used as backup protection to help reduce leaks reaching clothes or bedding.

To keep period underwear in good condition:

• rinse in cold water after use,
• machine wash on a cold or 30°C cycle or hand wash,
• avoid fabric softener and tumble drying,
• and air-dry

Over time, slight darkening of the gusset area is normal and does not affect absorbency or performance.

Read our full guide on how to wash period pants properly.

Period Stain Removal by Fabric — Quick Reference

Common period stain removal mistakes

These six mistakes are the main reasons period blood stains become permanent:

• Using hot or warm water: This is the single most common mistake, and it immediately sets the stain
• Putting stained clothes in the tumble dryer: Heat permanently bonds blood proteins to fabric
• Scrubbing aggressively: Pushes the stain deeper into fibres and can damage fabric
• Using bleach on coloured or dark fabrics: Strips dye and leaves yellow marks
• Waiting too long before rinsing: Dried blood is significantly harder to remove than fresh blood
• Checking the garment for stains after heat exposure: Always check before ironing or tumble drying; heat makes remaining stains permanent