Blood on underwear and bedding

Short answer: Rinse immediately in cold water. Warm water lets the proteins in blood bind to the fibers, making the stain much harder to remove afterward.

Cold water first, always without exception

Hold the garment under cold running water and let the water push the stain out from behind, not from the front where it sits closest to the surface. The faster you start, the better your chances of getting most of the blood out. See bamboo panties, which handle frequent cold rinsing without any damage.

Salt or hydrogen peroxide on a dried stain

Soak the garment in cold salt water for an hour and change the water once partway through for better results. On white fabric a little hydrogen peroxide can help, but always test it on an inner seam first so you know how the color reacts.

Wash cold afterward, not warm

Wash at 30 or 40 degrees and check the stain carefully before the garment goes into the dryer, where the heat can set any residue permanently. See bamboo bedding and period underwear, both of which handle the cold treatment well through many washes.

Fresh blood needs quick action

A fresh stain responds far better to cold water than one that has been allowed to set for hours or even days. React right away as soon as you notice the stain, even if it means pausing something else you are in the middle of.

Avoid rubbing the stain while rinsing

Rubbing pushes the blood deeper into the fibers instead of rinsing it out, just as with most other protein based stains. Let the water do the work, and press gently rather than rubbing hard against the fabric during the process.

Bedding needs the same method as underwear

The principle stays the same whether it is a pillow, a sheet or something else affected by an unexpected stain overnight. Rinse immediately under cold water, and do not let the stain dry in before you properly take care of it.

Wear darker colors during vulnerable periods

If you have periods where accidents are more likely, darker colors on both underwear and bedding can make a stain less visible if it happens. That does not solve the underlying issue, but it makes daily life a little easier until you find a steady routine.

Change right away if you can

If you can change into clean clothes immediately, do so, rather than waiting and hoping the stain will not get worse over time. Put the affected garment into cold water as soon as possible, even if you only manage the full treatment later.