From London's Ghost Acres
Cascarilla bark comes from plants of the Croton species, which are cultivated in Caribbean and shipped from the Bahamas. (https://en.wikipedia.org/wiki/Croton_eluteria)
Cascarilla is used as a Tonic and as a Carminative. It can also be combined with cinchona to make the mixture more agreeable to the stomach. It is used in the treatment of dyspepsia, flatulent colic, dysentery, and gangrenous thrush in children.
- 1 British Pharmacopoeia 1867
- 2 A Compendium of Domestic Medicine, 1865
- 3 References
British Pharmacopoeia 1867
Cascarilla Bark Cascarillae Cortex
Bark from Croton Eluteria, imported from the Barahams 
Characteristics “In quills, two or three inches in length, and from two to five lines in diameter, dull brown but more or less coated with white crustaceous lichens; breaks with a short resinous fracture; is warm and bitter to the taste; and emits a fragrant odour when burned.” Used in preparations:
- Infusum Cascarillae
- Tinctura Cascarillae
Preparations of Cascarilla
Infusion of Cascarilla / Infusum Cascarillae
- cascarilla bark, in coarse powder (I oz), infused in boiling distilled water (10 fl oz)
- given in a dose of 1-2 fl oz
Tincture of Cascarilla / Tinctura Cascarillae 
- cascarilla bark, bruised (2 ½ oz) and proof spirit (1 pint)
- dose is given in ½-2 fl drachms
A Compendium of Domestic Medicine, 1865
page numbers come from the pdf file, not actual document
Carminative (reduces gas) and tonic. When combined with Peruvian bark (cinchona) it can make PB more agreeable to the stomach, and increased the properties of PB. As a tincture used as a vehicle for preparations including iron, bismuth, other metallic tonics.
Treats: dyspepsia, flatulent colic, dysentery, diarrhoea, gangrenous thrush (esp in children). 
Remedies Containing or to be used with Cascarilla
- Infusions, Concentrated: of Cloves, Calumbo, Cascarilla, Chamomile, Gentian, Orange Peel, Quassia, Rhubarb, Roses, and Senna. Use of concentrated infusions allow for large doses of medicines to be administered, therefore, these medicines are well designed for medicine chests, and can be diluted depending on the required treatment.
- Tincture of Cascarilla: "exhibited in the debility of the bowels and stomach," also used in the place of Peruvian bark when PB acts as a purgative. 
Diseases Treated with Cascarilla
- Dysentery: used in the early stages of the disease, (can be replaced with the use of other barks), during the third stage of treatment that involves restoring and toning the intestines.
- Dyspepsia, or Indigestion: Abernethy's mixture contains an infusion of cascarilla, and to be taken before and after dinner.
- Sickness (276): infusions of Cascarilla can be used when "sickness proceeds from a chronic debility of the stomach"
Medical Articles Containing Cascarilla
- Stomachic Bitter: infusion of cascarilla
Prescriptions Containing Cascarilla
- Antacid Draught (Another) (328): tincture of casparilla. Used during dyspepsia
- General Medical Council of Great Britain, British Pharmacopeia, (London: Spottiswoode & Co.,1867), 72 https://archive.org/details/britishpharmacop00gene
- GMCGB, 72
- GMCGB, 187
- GMCGB, 324-25
- General Medical Council of Great Britain, British Pharmacopeia, (London: Spottiswoode & Co.,1867), 50 https://archive.org/details/britishpharmacop00gene
- Savory, 105
- Savory, 157
- Savory, 249
- Savory, 265
- Savory, 276
- Savory, 321
- Savory, 328