Blood is one of the few stains where doing the obvious thing makes it permanent. Reach for hot water, and the proteins in the blood cook into the mattress fibres — at which point you're no longer cleaning a stain, you're bleaching one. Cold water, patience and the right cleaner will lift most blood, even stains that have been sitting there for months.
Here's the method that actually works, split by how old the stain is.
The three rules that matter most
- Cold water only. Never hot, never warm. Heat sets blood permanently. This applies to the water, the cloth, and the air you dry it with — no hairdryer on a hot setting.
- Blot, don't rub. Rubbing pushes the stain sideways into clean fabric and deeper into the foam. Press a cloth down, lift it, move to a clean section, repeat.
- Work from the outside in. Start at the edge of the stain and move toward the centre. It stops you from spreading a small spot into a large halo.
One more: use as little liquid as you can get away with. A mattress is mostly foam, and foam that gets genuinely wet takes days to dry and can grow mildew inside where you can't see it.
Fresh blood: act in the first few minutes
If the blood is still wet, you can usually get all of it out with nothing but cold water.
- Strip the bed immediately and get the sheets into cold water. If you have a mattress protector, check whether the blood soaked through — often it hasn't, and you're done.
- Blot up the excess with a dry white cloth or paper towel. White matters: coloured cloths can transfer dye into damp fabric.
- Dampen a clean cloth with cold water — damp, not dripping — and blot the stain repeatedly, switching to a clean part of the cloth each time.
- Add a little dish soap if water alone isn't finishing the job. A few drops in a cup of cold water, applied with the cloth, will break down what's left.
- Rinse by blotting with a plain cold-water cloth, then press a dry towel down hard to pull moisture back out.
Dried or set-in blood: three methods worth trying
Once blood has dried, you need something that breaks down the proteins rather than just diluting them. Try these in order — gentlest first.
1. Salt or cornstarch paste
Mix cornstarch (or salt) with cold water into a thick paste, spread it over the stain, and leave it to dry completely — an hour or more. As it dries it draws the stain up out of the fibres. Scrape or vacuum away the crust and repeat if needed. It's slow, but it uses almost no liquid, which makes it the safest option for foam mattresses.
2. Hydrogen peroxide (3%)
This is the most effective household option for old blood. Standard drugstore 3% peroxide, dabbed on with a cloth or applied from a spray bottle, will fizz on contact with the stain — that reaction is what's lifting it. Let it sit a minute, blot, and repeat.
Two cautions. Peroxide can lighten coloured fabric, so test a hidden spot first — near the bottom edge or under the handle. And never mix it with ammonia, bleach or vinegar; the combinations range from useless to genuinely dangerous.
3. An enzyme cleaner
Enzyme-based cleaners are made to digest protein stains, which is exactly what blood is. They're sold for pet accidents and work just as well here. Spray lightly, leave it for the time the label specifies, then blot. This is usually what finally clears a stain that's months old.
A fourth option that sounds strange but works: unseasoned meat tenderizer mixed with cold water into a paste. It's an enzyme product by another name.
Period blood: same method, more of it
Menstrual blood behaves the same way chemically — cold water, no heat, blot rather than rub — but there's usually more of it and it has often had time to soak in overnight. The practical difference is that you'll likely need two passes: cold water and dish soap first to remove the bulk, then hydrogen peroxide or an enzyme cleaner on the shadow that's left. Don't judge the result until the mattress is fully dry, because a damp patch always looks darker than it is.
Drying it properly (this is where people go wrong)
A mattress that stays damp inside is a mildew problem waiting to happen. After blotting:
- Press a dry towel firmly into the area, standing on it if you need to, to pull moisture up.
- Sprinkle baking soda over the damp patch and leave it for several hours — it absorbs both moisture and odour — then vacuum thoroughly.
- Get air moving. A fan pointed at the mattress, or a window open, does far more than heat. If you're in LA, the dry air works in your favour here — an afternoon with the windows open and a fan running is usually enough.
- Don't remake the bed until the spot is completely dry to the touch, and don't put a waterproof protector back on a damp mattress — it traps the moisture in.
Memory foam and toppers need a lighter touch
Memory foam absorbs liquid readily and releases it slowly, so the paste method is your best starting point and heavy spraying is the thing to avoid. Never soak foam, and never put a foam topper in a washing machine — the agitation tears it apart. Spot-clean a mattress topper the same way you would the mattress, and dry it flat with airflow on both sides.
A removable, machine-washable cover is a different story — check the care label, wash cold, and air dry.
The thing that stops this happening again
A waterproof mattress protector is the single most cost-effective thing you can buy for a mattress. Blood, spills and sweat stop at the protector, which goes in the wash; the mattress underneath stays clean and the warranty stays intact, since most manufacturers will void a claim on a stained mattress. If you already have one, our guide to washing a mattress protector covers doing it without ruining the waterproof layer.
For everything else that ends up on a mattress, see our full guides to cleaning a mattress and removing stains of every kind.
Frequently asked questions
How do you get dried blood out of a mattress?
Loosen it first with a cold-water and cornstarch paste left to dry, then treat what remains with 3% hydrogen peroxide or an enzyme cleaner. Blot rather than scrub, and expect to repeat the process two or three times on an old stain. Never use warm water — it locks the stain in further.
What takes blood out of a mattress?
For fresh blood, cold water and a few drops of dish soap. For dried blood, hydrogen peroxide, an enzyme cleaner, or a salt or cornstarch paste. Baking soda helps afterwards by absorbing remaining moisture and odour. Anything hot, and any bleach, makes the situation worse.
How do you get period blood out of a mattress?
Exactly as above, in two passes: cold water plus dish soap to lift the bulk of it, then hydrogen peroxide or an enzyme cleaner on the remaining shadow. Because there's usually more volume, blot longer than feels necessary and dry with a fan before remaking the bed.
How do you get old blood stains out of a mattress?
Old stains need an enzyme cleaner more often than not — peroxide alone may fade them without removing them. Apply, wait the full dwell time on the label, blot, and repeat over a couple of days rather than trying to force it in one session. Some very old stains lighten substantially but never disappear entirely; at that point a protector or a topper is the practical fix.
How do you get blood out of a mattress protector or topper?
Check the label first. Many protectors are machine washable on cold with a gentle cycle — rinse the blood out in cold water first, then wash, and air dry rather than tumbling on heat. Foam toppers can't be machine washed; spot-treat them the same way you would a mattress and dry them flat with air moving over both sides.
Does hydrogen peroxide damage a mattress?
Used at the standard 3% drugstore strength and applied lightly, it's safe on most mattress fabrics. It can lighten colour, though, so test an out-of-sight area first. The bigger risk is over-saturating the foam underneath — use it sparingly and blot as you go.
When cleaning isn't the answer
If a stain has soaked deep enough that the mattress smells, or the bed was already sagging and uncomfortable, cleaning it is polishing a problem. Take our two-minute sleep quiz to see what would actually suit you, or visit any of our five LA showrooms — every mattress comes with free same-day or next-day delivery across Los Angeles and a free 120-night comfort guarantee.
