A dried substance of mucilaginous character abstracted from several species of sea weeds (marine algae) growing along the coast of Asia. Most of it comes from Japan. Dose, 1 to 4 drachms.
Common Name: Agar-agar.

Description.—Agglutinated membranous pieces, tough or brittle accordingly as it is damp or dry. The pulverulent form is most commonly used. It is a coarse, buff-colored granular powder, having practically no odor or taste. It swells to a soft magma in the presence of water.

Action and Therapy.—Agar has no action upon the human body nor is it in turn affected by the digestive ferments or intestinal flora. It has the property of absorbing moisture and swelling to a soft mass, and for this purpose is given in constipation as a mechanical laxative; rendering the best service when intestinal secretion is scanty, and in consequence, the feces are abnormally dry. From one teaspoonful to two heaping tablespoonfuls may be given once or twice a day in dry form alone, or mixed with some cereal at meal-time. Biscuits, bread, and crackers are prepared from it and may be procured in the general trade. Agar is also used as a culture medium in making labaratory cultures.

The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.