Strictly speaking, you don't need a special cabinet just for first aid supplies.
You can stow gauze and band-aids in your medicine cabinet, the one with the mirror. But Kikkerland, purveyors of Moleskine notebooks, built a few features into this little aluminum cabinet that have made us take a second look.
The see-through cross in the corner announces the cabinet's purpose to anyone visiting your bathroom -- say a new babysitter who wouldn't otherwise know where to find that instantly soothing band-aid.
Separating out first aid neccessities is also useful if, like us, you tend to sort through your medicine cabinet all too infrequently, and never seem to notice that you're out of Bacitracin until the moment you need it.
More importantly, this cabinet locks, so you can keep prescriptions and other potent substances out of the reach of small hands... and away from the eyes of snooping houseguests. Just remember to give the babysitter the key.
Available here for $79.