Ordinary mustard has long been employed as a plaster wherever it is desirable to quickly draw the circulation outward or away from the head or other congested portions of the body. For such purposes one part of mustard and four parts of wheat flour made into a paste with warm water will be sufficient. This should be spread over muslin and applied for not longer than an hour, as a blister is liable to follow. Stronger plasters may be prepared for more urgent cases. An infusion of mustard in a bucket of water is excellent for a foot bath when it is desired to call the blood from the brain, lungs, etc. Mustard emetics are quickly effective in cases of poisoning. A tea-spoonful of mustard to a large teacupful of boiling water, drank in one dose, will usually be followed promptly by vomiting, especially if the finger is thrust into the throat.
Lobelia with some Capsicum is by far preferable to mustard for the purpose and the after effects are not as bad. In using mustard plaster, never blister the skin. To do so is harmful to say the least.