How many minutes should you keep salt on a mouth ulcer?

It is generally not recommended to place salt on mouth ulcers. In fact, it can cause further irritation and pain. Instead, many suggest a variety of remedies, such as rinsing the mouth with warm saltwater or using over-the-counter numbing agents or gels to help relieve pain and promote healing. It's always best to consult with a healthcare professional if you have persistent or severe mouth ulcers.