Occurrence—Pepsin is the natural enzyme—a proteolytic ferment, obtained from the glandular structure of the lining membranes of the fresh stomach of the domestic hog—sus scrofa. It is an essential constituent of the gastric juice.

Description—Pepsin occurs in the form of scales, granules or as an amorphous powder. It is yellowish-white, translucent, has a characteristic odor and a peculiar, moist, elastic feel to the touch. To the taste it is slightly acid, bitter, saline. It is soluble in 100 parts of water, but by the addition of hydrochloric acid its solubility is greatly increased. It is insoluble in alcohol and chloroform.

It should have a digesting power equal to 3,000 times its own weight of freshly coagulated egg albumen.

Administration—It is given in the form of the powdered pepsin or as saccharated pepsin in doses of from three to ten grains. The essence of pepsin in dram doses is an excellent form for administration.

Physiological Action—Pepsin digests the nitrogenous constituents of food, converting them into peptones. Its action is increased by the addition of hydrochloric, lactic and citric acids.

Therapy—A deficiency of the digestive ferments in the stomach, evidenced in painful or imperfect digestion, is largely supplied by the administration of pepsin. Whenever severe disease induces inactivity of the glandular organs of the body, there is apt to be inefficient action of the peptic glands, and consequently a deficiency of pepsin. This is the case after severe shock, either from injury or from surgical operation, in neurasthenia, and in brain or spinal disease; also in severe acute inflammatory disease, in protracted fevers, in heart disease, in diabetes, and especially in gastric ulcers and cancer. In all these cases, there being atonicity with enfeeblement of functional operation, pepsin in conjunction with tonics, stomachics and hydrochloric acid is often demanded.

Infants fed on artificial food are benefited by the use of pepsin. It may be given during or at the end of the meal, and is often productive of excellent results.

Where malnutrition is marked, and the growth and development of the child retarded from this cause, this agent is sometimes the means of accomplishing a complete cure. In diarrhoea in childhood from indigestion, a most important factor in the treatment, is the perfect digestion of the food. A little skill on the part of the physician can often so adjust the administration of pepsin as to satisfactorily accomplish all desired results in such cases, often without the use of astringents. Mild intestinal antiseptics are often necessary in conjunction.

It is argued that artificial digestion, by doing the work of the gastric juice, is apt to produce impairment of the function of the gastric glands because of inactivity or non-use. It is the observation of those who have used pepsin, pancreatin and papoid, that they act not only as assistants to the digestive processes, but that they stimulate the gastric glands, and impart real tone and renewed functional energy. This may be in part due to the immediate improvement in general nutrition from the rapid appropriation of the more perfectly digested food. These digestives exercise a sedative influence also upon the stomach when there is nausea and irritation due to the presence of undigested food.

The partial predigestion or peptonizing of the food of infants suffering from malnutrition is generally recognized as an essential process. This process is adopted with invalids suffering from gastric disorder, and is advised also in preparing milk for administration per rectum, when no food can be introduced into the stomach. In this case a few grains of pepsin added to the prepared enema, whatever its character, is of great assistance in its appropriation.

Pepsin in solution has been used to dissolve the false membrane in croup, and the exudate in diphtheria. It has also been injected into the urinary bladder to dissolve blood-clots, and applied to indolent ulcers to destroy unhealthy tissue and stimulate the surface to normal granulation.

The American Materia Medica, Therapeutics and Pharmacognosy, 1919, was written by Finley Ellingwood, M.D.
It was scanned by Michael Moore for the Southwest School of Botanical Medicine.