This section is from the book "Materia Medica And Therapeutics - Vegetable Kingdom", by Charles D. F. Phillips. Also available from Amazon: Materia Medica And Therapeutics: Vegetable Kingdom.
Physiological Action. - Nothing whatever is known about this. It is supposed by some (on empirical evidence) that taraxacum acts on the liver; but there is no scientific proof of the fact. It has also been credited with diuretic powers, as the French name for it - "pissenlit" - indicates; but again there is no evidence to justify the notion.
Therapeutic Action. - Although there is no exact physiological knowledge respecting the action of dandelion, there is no reason to doubt that it has some medicinal efficacy. The nature of that action, however, has in all probability been completely misunderstood by the majority of those who have spoken well of it. It has been supposed to act specifically on the liver; but the very magnitude and diversity of the statements respecting its action on that viscus, expose them all to grave suspicion. It has been supposed not merely to specifically increase the biliary secretion (as to which Dr. Hughes Bennett's experiments are flatly contradictory), but to cure chronic inflammation, indolent enlargements, and even to prove effective in commencing scirrhus of the liver. A great deal of the evidence on which such statements rest has been based on medication in which powerful drugs have been given in conjunction with it. For my own part, the only distinctly efficacious action of taraxacum appears to be as a mild stomachic, and possibly a duodenal tonic. It certainly does good in simple atonic dyspepsia, and even (temporarily) in failures of digestion which depend upon disease of the liver and other viscera. But there seems to me to be a complete absence of any proof that it is a specific remedy for biliary disorders. It appears to act solely as a tonic to the earlier digestive functions, and the extent to which it will relieve disorders of these depends wholly on the degree in which the original cause was severe, and continuous in operation. There is no pretence for believing that it modifies distinct organic changes in any viscus. (From Rutherford and Vignal's experiments it "appears that taraxacum is a very feeble hepatic stimulant." - (Brit. Med. Jour., Nov. 13, 1875.))
Preparations and Dose. - Extract. Taraxaci, gr. xx. - 3 j. (1.30
- 4.); Extract. Tarax. Fluid., 3 i. - ij. (4. - 8.); Infusum Tarax.,
(30. - 120.); Succus Tarax., 3 j. - iv. (4. - 15.). No doubt the freshly prepared succus is the best form in which to give taraxacum; but there is much difference in opinion as to whether the thick albuminous juice obtained in winter, or the thinner and more acrid juice of early summer, is the more active. (Phillips.)