Aloe, “commonest domestic medicine”

Continuing my series on the symbology of the various elements found on the Royal Pharmaceutical Society’s arms (see Pharmacy and the olive branch of peace), I turn now to the device in the shield’s second quarter (ie, top right) — an aloe plant.

At the time of the Society’s foundation in 1841 almost all medicines had a botanical origin, and formulations based on aloe extracts were among the most widely used.

Even 70 years later, the second (1911) edition of the Society’s British Pharmaceutical Codex says: “Aloes in one form or another is the commonest domestic medicine, and is the basis of most proprietary or so-called ‘patent’ pills.”

Aloe is one of many botanical products that have been used for their purgative action. It was used in the form of extracts, tinctures, pills and tablets prepared from several of the 299 species to be found in the genus Aloe. Their principle active constituent is aloin, an anthraquinone glycoside.

Despite its representative role on the Society’s shield, aloe is far from ideal as a laxative, although it may be no worse that the alternatives available in the 1840s. One problem is that aloe takes a long time to act, typically 15–18 hours, since it has no effect until it reaches the colon, where it induces bowel movements by increasing peristaltic contractions.

Another problem with aloe is that it tends to be griping. To moderate this tendency, it was commonly employed in combination with a carminative. The aforementioned edition of the BPC lists some 30 compound preparations, many including ingredients such as myrrh, liquorice, cardamom, caraway, cinnamon and nutmeg.

Because of side effects and potentially serious adverse effects, perhaps including carcinogenicity, aloe is now rarely used internally. It is, however, still much used externally, mainly in cosmetic and toiletry products. A gel extracted from the leaves has been used to sooth wounds and burns and for skin conditions such as eczema and ringworm, although evidence that it greatly increases wound healing times suggests that it is not an ideal product.

Nevertheless, despite its limitations, it is easy to see why in the 1840s the aloe was seen as an ideal choice to represent all medicinal plants.