Mustard plasters are poultices made from crushing mustard seeds. Different recipes call for adding other spices and herbs to the mixture, creating a paste that is wrapped in a protective dressing and applied to the area of the body where discomfort is present. Traditionally, the mustard plaster is used to help alleviate chest congestion during a cold or flu, or as a way of helping stiff muscles to relax.
One of the reasons for the popularity of the mustard plaster is the heat that the poultice generates. When applying this heat to the chest, it can help break up congestion and allow the individual to breathe with less difficulty. At the same time, applying a mustard plaster to an aching back can help relax sore muscles and ease the pain in a very short period of time. In the age before modern ointments and creams, many homes kept the ingredients for a mustard plaster on hand, especially during the winter months.
A basic mustard plaster recipe will make use of powdered mustard seed. The powder can be purchased from health food stores and spice shops, or created by grinding the seeds by hand, or by using a food processor to create the powder. Small amounts of white flour, water, and egg white are added, making it possible to work the powder into a paste. This paste is applied to some type of cloth, usually cotton or flannel, and folded into a poultice. The finished plaster is then applied to the area of the body that is experiencing discomfort.
There are a number of variations of this basic recipe. Some call for omitting the water, but adding extra egg whites. The idea behind this approach is that the egg whites purportedly help to minimize the chances for blistering the skin. Other recipes call for adding some cayenne powder to the mixture; supposedly, the capsicum in the powder helps to increase the heat of the mixture, allowing the poultice to deliver more heat in a shorter period of time.
While many people swear by the efficacy of the mustard plaster, it is important to note that there are some restrictions to consider. The poultice should never be applied to an open wound, or on a part of the body where some type of skin irritation already exists. The plasters should not be left on for extended periods of time, or blistering is highly likely. Last, some people are allergic to mustard seeds, which means the poultice could create more health problems than it helps.