Pelargonium sidoides: traditional knowledge vs scientific evidence

South African plant medicine

Pelargonium sidoides, also known as South African geranium, is one of several species of the genus Geraniaceae that are important traditional medicines in South Africa. The plants of this genus are often referred to by their original Khoi-Khoi name rabas. The fleshy, bright red tubers or rhizomes have been widely used by different cultural groups, mainly to treat diarrhoea, dysentery and gastrointestinal afflictions of infants. They were amongst the first to be recorded by early explorers to the region.

The Sesotho vernacular name of Pelargonium sidoides is khoaara e nyenyane, literally meaning “growing attached to stones or rocks”. The plant stands apart from the rest of the genus, due to its maroon-red to black petals. It also is unique due to its development into an internationally-consumed, “evidence-based” phytomedicine known as umckaloabo® or kaloba®.

Fig. 2. (A) commercial plantation; (B) harvested raw material; (C) flowering plant with leaves and flowers; (D) the tuberous root in cross section.
Credits: Van Wyk (A, B, D), A. Oskolski (C). 

Early records

The most detailed account of the value and uses of Pelargonium sidoides is that of Sir Andrew Smith, a scholar with a passion for botany. He wrote of the action of the herb, noting that dysentery differs from diarrhoea in being “attended by inflammation and fever” and other complications. He wrote, “As these maladies proceed from many different causes, and commonly enough involve complications, it cannot be supposed that a simply drug can be relied on to cure them. At the same time singular benefit has often been derived from certain plant substances, when the usual course of medicine has failed, as if they aid the curative powers of nature to rally and overcome the disease”. As such, Smith made a strong case that Pelargonium sidoides should be regarded as a general tonic.

Stevens’ cure

Another, apparantly unreliable claim was made that the roots of Pelargonium sidoides have been utilised in traditional medicine of South Africa for the therapy of tuberculosis (TB) (see Fig. 1D). The claim was made by Charles Henry Stevens (Fig. 1A) from Birmingham UK, creator of “Stevens’ cure”. According to his account, Stevens was sent to South Africa by his doctor in order to recover from pulmonary TB. There he met a local healer who treated him with a root concoction. Three months later he felt well, returned to the UK and was pronounced free of TB. After this, Stevens then started his lifelong efforts to commercialise his “discovery”.

Stevens had some degree of success with his venture. His remedy received attention and was utilised by a French-Swiss physician treating TB patients. Some case reports were released attesting to the effectiveness of the remedy (Fig. 1C). At one point he employed 50 people in the manufacture. His activities were somewhat hampered by an accusation of quackery and fraud in a British Medical Association publication (Fig. 1B), leading to a failed libel action. The war also caused disruption to supply of raw material. After his death in his early 60s, his son sold the business to a German company.

Fig. 1. : (A) Charles Henry Stevens, ca. 1925; (B) cover of British Medical Association – Secret Remedies: What they Cost and What they Contain published by the British Medical Association, 1909; (C) Cover of Sechehaye – The treatment of tuberculous affections with Umckaloabo, 1930; (D) Dust jacket of Anonymous – The Doom of 150,000 People, 1931. 
Credit – Thomas Brendler


“Umckaloabo” is the name used by Stevens in his book for his TB medicine, a name that has persisted to this day. However all contemporary attempts to explain the origin of the name are unconvincing. The ethnicity of Stevens’ healer and hence the language he used remains uncertain. Further confusion is caused by Smith and later authors, who recorded the vernacular name (in isiXhosa) as iyeza lezikhali, ikhubalo, uvendle and icwayiba. The term umckaloabo may indeed be an invention of Stevens, based on South African languages, intended to create a sufficiently mysterious image for his remedy in order to further its marketability.

The origins of “umckaloabo” is also unclear. It was claimed to have been introduced from Lesotho. However, South Africa, the Gold Coast and Liberia are given in Stevens’ book as the three sources of material of this mysterious plant, which was said to belong to the family Polygonaceae. It may therefore be speculated that it could have been a species
of Rumex (a genus widely used in traditional medicine in South Africa). All these “facts” may have been invented in an attempt to protect the secrecy of the medicine and its source of raw material. It took until well into the 1970s for the plant ingredient of the remedy finally to be identified by Dr. Sabine Bladt, sparking renewed interest and clinical research into the herb.

Succesful phytomedicine

As research progressed, a proprietary extraction technique was developed and perfected to yield the extract EPs 7630. This ethanolic root extract is manufactured by Dr Willmar Schwabe Pharmaceuticals, Germany, and registered by ISO Pharmaceuticals, Germany. In the early 1990s the product was “relaunched”, this time supported with data on efficacy and safety, provided by several high-quality randomised controlled trials (RCT). The remedy was marketed in Germany and abroad with great success. The annual turnover in Germany rose from 8 million euro in 2001 to 80 mil euro in 2006. Umckaloabo® received a full market authorisation by the German drug regulatory agency in 2005 and became listed in the European Pharmacopoeia. Currently, P sidoides is grown on specialized farms in South Africa using ecological cultivation methods.

Clinical data

So the question arises. What is the most indicated use for Pelargonium sidoides?

One salient point to consider is that a RCT is high up on the heirarchy of clinical evidence. While TB is not a major modern day health concern, Pelargonium sidoides has been extensively tested for other respiratory issues, especially acute bronchitis. In fact, the bronchitis clinical trials comprise the core of the data that drove the commercial success of the extract. Further, there are now systematic reviews with meta analysis on this specific intervention. This is the highest available evidence. As such, in contemporary practice, naturopaths and Western herbalists utilise the herb for repiratory afflictions, in line with the current evidence. Practitioners are widely encouraged in training and within the industry to be “evidence-based” in their practice. While often the traditional uses of herbs are consistent with current evidence, this is one case where current use is incongruent with the traditional folk use.

On the other hand, a quick appraisal of the literature, will reveal an important issue with the data. Specifically looking at the trials on acute bronchitis, all of them are funded by the manufacturer and were undertaken by the same research team, some of whom were directly employed by the manufacturer. So, considering that the trials were of high quality, and that the data was scrutinised in a Cochrane report, then the funding issue should not matter, right? Well, not necessarily. It is well established that clinical trials with conflicts of interest have a high risk of bias. In particular, if a trial is funded by a manufacturer, it has a high risk of profit bias.

So the question still remains. What is the most indicated use for Pelargonium sidoides? And a new question arises, what should we go with, the traditional knowledge or the scientific evidence. The answer to these questions may be very nuanced and not as straightforward as it may appear.

* Much of this information was taken from Brendler T, Van Wyk B-E. A historical, scientific and commercial perspective on the medicinal use of Pelargonium sidoides (Geraniaceae). J Ethnopharmacol. 2008;119(3):420-33

* Feature photo by to.wi (Flickr)