What should you do if someone has a nosebleed?

When dealing with a nosebleed, pinching the nostrils together is the correct action to take. This method helps to apply pressure to the bleeding site in the nasal cavity, which can effectively reduce or stop the blood flow. The proper technique involves having the person sit up straight to prevent blood from flowing down the throat, which can lead to choking or nausea, and pinching the soft part of the nose just below the bony bridge.

The duration for which you should maintain this pressure is typically around 5 to 10 minutes, and during this, it's important for the person to breathe through their mouth. This compression encourages clotting and can significantly help in managing the bleeding effectively.

Other approaches, such as lying down or using hot compresses, could potentially complicate the situation. Lying down might increase pressure in the blood vessels of the nose and worsen the bleeding, while hot compresses can cause more blood flow, thus not being advisable. Encouraging someone to sneeze is also not a safe option as it can further aggravate and reopen the bleeding vessels.