It's long been a fixture of American medicine cabinets, but hydrogen peroxide is not the treatment for cuts you might think it is. In fact, the properties in it that kill bacteria can actually damage healthy cell tissue. (The same is true of other disinfectants, such as alcohol and iodine.) That rarely causes serious harm, but it could slow healing time. Studies show that for most cuts and scrapes, rinsing thoroughly with water and cleaning the surrounding area with plain soap is at least as effective at preventing infection as hydrogen peroxide. And it's less irritating to the wounded tissue. Use lots of water, at a high enough pressure to flush out debris.
Hydrogen peroxide shouldn't be your first-line treatment for cuts, but it's not a bad idea to stash some in an emergency kit for when you don't have access to clean water. Keep some rubbing alcohol in the kit for disinfecting surfaces and various first-aid tools such as tweezers.