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A poultice, also called cataplasm, is a soft moist mass, often heated and medicated, that is spread on cloth over the skin to treat an aching, inflamed, or painful part of the body. It can also be a porous solid filled with solvent used to remove stains from porous stone such as marble or granite.

Contents 1 Etymology 2 Uses of Poultice on Horses 2.1 When not to use a poultice 2.2 Types of poultice 2.3 Materials 3 Use of Poultices in Stain Removal

The word "poultice" comes from the Latin puls, pultes, meaning "porridge."

A poultice is a common treatment used on horses to relieve inflammation. It is usually used on the lower legs, under a stable bandage, to focus treatment on the easily-injured tendons in the area. Poultices are sometimes applied as a precautionary measure after the horse has worked hard, such as after a cross-country run, to prevent heat and filling. They are also used to treat abscess wounds, where a build up of pus needs to be drawn out. Abscesses are fairly common in the foot of the horse, as the horse may tread on something and puncture the sole of its foot, allowing it to become infected. This is a particular risk if the horse pulls a shoe off and tread on one of the nails.

Poultices may also be heated and placed on an area where extra circulation is desired. A hot poultice increases heat and circulation, a cold poultice decreases heat and inflammation. If a hot poultice is used, care must be taken to ensure that it is warm but not too hot as a poultice can hold in heat for a considerable amount of time and may burn the treated area.

The poultice should be left on the horse for 12-24 hours. Following removal, it is best to wash off any remaining poultice with soap, and to thoroughly dry the legs. When poultice is used by itself (without wraps), it will usually be completely dry. Dry poultice is much easier to remove with a curry or brush, or the fingers; it will chip and fall off.

• Poultice should generally not be applied over an open wound, as it may slow the healing process or cause infection.
• Generally, it is not a good idea to poultice a leg that is showing signs of injury, as it may mask the symptoms before the vet has a chance to assess it.
• Care should always be taken to follow the directions on any commercially-bought poultices. If the poultice contains medicines or irritants that could potentially blister, it is best to ask the advice of your vet.

• 'Animalintex' is a brand name poultice made from an absorbent material
• Bran is also used as a poultice as it is so absorbent. It is packed into the wound and then covered with a piece of sacking or similar material, before being bandaged onto the foot or site of the wound.
• There are also many commercial poultices that are ready-made.

• 'Poultice boots' for use on hooves are available to buy from tack shops and whilst not essential, help to keep the poultice in place. A piece of sacking used with strong duct tape will do just as well.
• Nappies/diapers may also be cut to size to use as a poultice as they are very absorbent and will help to draw out pus. They are especially useful when applying a poultice to the hoof.
• Leg quilts and bandages are often used over the poultice to help keep it in place.
• A covering over the poultice, such as soaked brown paper bags, newspaper, waxed paper, elastic gauze, or plastic wrap can be used to help keep the poultice moist, and to keep it from getting onto the wraps. However, newspaper and other printed paper may contain irritating dyes. When using plastic wrap, care must be taken not to put it on too tightly.

Stone is a porous material which is susceptible to staining. Granite and marble are frequently used in residential construction of bathrooms and kitchens and are susceptible to a variety of stains. Poultices are a useful technique for removing such stains, but the chemistry of the process is rarely understood by those who use them.

Chemistry of Stains

From a chemical standpoint, a porous stone becomes stained when a solution containing a solute penetrates its surface and then evaporates leaving the solid solute behind within the stone. Alternatively, grease may penetrate the porous surface and remain within the stone without evaporating. In either case, the stone will become visibly "stained."

Chemistry of Poultices

A poultice is a malleable mass of a porous material (paper, whiting, diatomaceous earth) filled with a solvent which can be applied to the surface of the stone. The choice of solvent (ammonia, acetone, alcohol, etc.) should be something likely to dissolve the solute or grease causing the stain. As the solvent penetrates the surface of the porous stone containing the stain, it forms a single continuous solution between the stone and the poultice on the surface. The poultice needs to be kept moist and is usually covered to allow time for the solvent to sufficiently penetrate the stone and dissolve the staining material, be it grease or solute. The solute will then equilibrate by passive diffusion between the stone and the poultice. After an adequate time for this process to occur, the poultice is removed and with it the solution containing a portion of the dissolved solute or "stain." Multiple repetitions of the process will eventually decrease the concentration of the solute or "stain" within the stone until it is invisible or minimally visible.

Misconceptions

Lay discussions of poultices frequently suggest that this is an active process, "sucking out" stains from the stone. In fact, as detailed above, the process is strictly one of passive diffusion of solute within a solution shared by two porous materials in contact. The volume of solvent within the poultice compared to the volume of solvent within the stone determines the fraction of solute or "stain" which can be removed with each application. Another common misconception is that a poultice must be allowed to dry before it is removed. This is totally erroneous and actually harmful to stain removal. If the poultice is allowed to dry, the concentration of solute or "stain" within the poultice will increase which will result in back-diffusion of the solute into the solvent remaining in the stone. A poultice used for stain removal should be removed while it is still moist. It is repetitive applications, not drying of the poultice, which effects removal of the stain.