Needles can be used along with Thread to stitch a deep wound. Alternatively if a needle is not available or there is no thread, a suture needle by itself can also be used, and it will cause the player less pain than using a needle and thread. Needles can be found within medicine cabinets.
A needle is a multi-use item, and unlike a suture needle, it will not disappear.
Needles are also used for crafting house items like a mattress.