Use cold water, never hot. Blot up as much blood as you can with a clean white cloth, lift the rest with cold water and a little clear dishwashing liquid working from the outside in, and treat any shadow that remains with a carefully spot-tested hydrogen peroxide solution on a light, colourfast carpet only. The one rule that decides everything is temperature: blood is a protein, and heat cooks it into the fibre for good, so hot water turns a workable stain into a permanent one. Act quickly and a fresh blood stain usually lifts well. Dried, old blood is much harder, because the protein has coagulated and bonded to the pile.
Why blood is a protein stain, and why heat sets it forever
Blood is a protein-based stain, in the same family as other protein and grease stains like milk, egg and sweat. Protein reacts to heat exactly the way an egg does in a hot pan: it coagulates, hardens and locks onto whatever it is touching. Pour warm or hot water on a blood stain and you effectively cook it into the carpet fibre, which is why so many blood stains become permanent the moment someone reaches for the kettle or a steam cleaner. Cold water keeps the protein soluble and liftable. The second factor is time, because as blood dries it clots and grips the fibre, so a fresh spill is far more forgiving than one found the next morning.
Act fast: blot with cold water
Press a clean white cloth or paper towel straight down onto the blood and lift it away, turning to a dry section as it loads up. Do not rub or scrub, because rubbing spreads the stain wider and pushes it deeper into the pile. Work from the outer edge inward so the stain does not grow. Get up as much as you can by blotting alone before any solution goes on, since every bit you lift now is protein that cannot dry and set.
Step 1: cold water and dishwashing liquid
Mix a few drops of clear, mild dishwashing liquid into about two cups of cold water. Dampen a white cloth, do not soak the carpet, and dab the stain from the outside in, switching to a clean part of the cloth as the blood transfers. Rinse by blotting with a cloth wrung out in plain cold water so no soapy residue is left behind to attract dirt later. Repeat patiently. On a fresh spill this stage alone often lifts the great majority of the stain.
Step 2: salt paste, or hydrogen peroxide for what remains
For a stain that is drying or stubborn, a paste of salt and cold water can help draw it out: apply it, let it sit briefly, then blot and rinse with cold water. For any shadow left on a white or genuinely colourfast light carpet, a three-percent hydrogen peroxide solution can lift the last of it. Understand the trade-off first: peroxide is a mild bleach and cannot tell the difference between the blood and your carpet's own colour, so it can leave a pale patch on anything other than white. It also fizzes on contact with blood, which is normal, but that reaction is why you must spot-test a hidden area, apply sparingly, and stop the moment you are unsure. Never use peroxide on wool.
Dried or old blood stains
A dried stain needs to be softened before it will lift. Loosen any crust gently, then lay a cloth dampened with cold water over it for several minutes to rehydrate the protein before you start blotting with the dishwashing-liquid solution. An enzyme-based cleaner is genuinely useful here, because the enzymes break down the protein itself rather than just diluting it, the same reason they work so well on protein-based pet stains. Even so, old blood that has fully set may not come out completely at home, and you are better off stopping before you damage the pile, see our guide to removing set-in stains.
Blood on a wool carpet or rug
Wool changes the rules. It is a protein fibre itself, so it is easily damaged by the alkalinity and bleach in many stain products, and it can felt or bleed colour if treated harshly. Keep strictly to cold-water blotting with a very mild wool-safe detergent, use as little moisture as possible, and leave peroxide and salt out entirely. A blood spill on a Persian or other hand-knotted rug should not be experimented on at all, because the natural dyes and foundation are at real risk, which is why we treat wool with chemistry matched to the fibre rather than off-the-shelf removers. See also products that damage carpet.
Blood on a mattress or upholstery
The cold-water principle is the same on a mattress, where you cannot rinse freely, so use a barely-damp cloth and blot rather than soak, then let it dry fully with airflow. Our dedicated guide covers this in detail: see how to remove blood stains from a mattress. On a sofa or chair, check the fabric cleaning code first, see the W, S, WS and X fabric codes explained: a water-based method suits "W" and "WS" fabrics, an "S" fabric is solvent-only, and an "X" should be vacuumed and left to a professional. We clean fabric and microfibre upholstery, not leather or genuine suede.
What not to do
- Do not use warm or hot water. Heat cooks the protein and sets the stain permanently. Cold only.
- Do not rub or scrub. Blot straight down. Rubbing spreads the stain and frays the pile.
- Do not reach for a steam cleaner. The heat is exactly what sets blood into the fibre.
- Do not use peroxide on wool, or on any coloured carpet without a hidden spot test first.
- Do not soak the carpet, which pushes blood into the backing and risks a returning stain as it wicks back up.
When to call a professional
Call a professional for a large spill, dried or old blood, any blood on a wool carpet or hand-knotted rug, or a stain on a light carpet where the faintest shadow will show. A professional can rehydrate and lift set protein with the right chemistry and extract with controlled moisture, giving the best chance of clearing the stain without bleaching or over-wetting the carpet. We are honest up front about what is realistically removable, see our honest take on permanent stains, because a very old, fully set blood stain cannot always be completely reversed.
Common questions
How do you get blood out of carpet?
Blot up the blood with a clean white cloth, then dab with a solution of clear dishwashing liquid in cold water, working from the outside in and never using hot water. Rinse by blotting with cold water, and for a stubborn shadow on a white or colourfast carpet, spot-test and apply a three-percent hydrogen peroxide solution sparingly. Act fast, because fresh blood lifts far more easily than dried.
Does dried blood come out of carpet?
Sometimes, but it is much harder than a fresh stain. Rehydrate the dried blood with a cold, damp cloth for a few minutes first, then blot with a cold dishwashing-liquid solution, and use an enzyme cleaner to break down the set protein. Old, fully set blood may not come out completely at home, and a professional gives the best chance without damaging the pile.
Why should you never use hot water on blood?
Because blood is a protein, and heat coagulates protein and bonds it permanently to the carpet fibre, exactly as heat cooks an egg. Hot water, or a steam cleaner, turns a liftable blood stain into a set-in one. Always use cold water on blood, from the first blot to the final rinse.
For blood stains that will not lift at home, see our carpet cleaning and upholstery cleaning services, or request a free quote.