Mustard plaster

A mustard plaster, also known as a blister, is a poultice of mustard seed powder spread inside a protective dressing and applied to the body to stimulate healing.

It can be used to warm muscle tissues and for chronic aches and pains.

[1] It was once part of conventional medical treatment,[2] and available in prepared versions in pharmacies.

[3] Mustard plasters were used for aches and pains, including rheumatism, arthritis, and sore muscles.

[4] If left in place for too long, it can produce first-degree burns to the skin.