This section is from the book "A Practitioner's Handbook Of Materia Medica And Therapeutics", by Thos. S. Blair. Also available from Amazon: A Practitioner's handbook of Materia Medica and Therapeutics.
Rheum. In large doses rhubarb is cathartic, combining an astringency that renders its action easy, yet satisfactory. Used to free the bowels of offending matter in diarrhea and in atonic states of the bowel. It combines well with aloes. Powdered root, 20 to 40 gr., purgative; 10 to 20 gr., laxative. The extract is given up to I5 gr., and the fluidextract as high as I f3, but usually not over 30 I.
In small doses the tonic properties of rhubarb are secured. It is not used uncombined to any extent, but enters into various formulae. For infants with acid diarrhea and the gastro-intestinal irritation incident to dentition, quite small doses of the Syr. rhei aromat. are indicated. The old eclectic formula, now incorporated into the National Formulary as Syr. rhei et potassii camp. and known as "neutralizing cordial," is the very best antacid stomachic ever devised for children. The dose is from 74 to 4 f3, according to age and conditions. Children seldom demand over I teaspoonful.