A number of medicinal plants that have enjoyed widespread historical use before falling into disuse in modern times have been rediscovered as potential new therapeutic agents. Euphorbia peplus — also known as petty spurge, radium weed or cancer weed — is one of these plants, with research supporting many of the traditional medical applications for which it was used in folk medicine. It is a group of chemicals found within the latex secretions of this small, green suculent plant that is being employed as a treatment for warts, sunspots, tumors, basal cell carcinoma and other skin conditions. Research into the safety and efficacy of the plant for the treatment of these and other conditions is still in its infancy as of 2011, with considerable more work needed to determine whether Euphorbia peplus has any application in contemporary medicine.
The latex contains the pharmacologically active diterpene ester ingenane, also known as the research chemical PEP005. It also contains levels of the toxic diterpene 5-deoxyingenol. Ingenane has been studied for its cytotoxic properties. Several studies have found that it, just as a number of pharmaceutical treatments for cancer, is an activator of Protein Kinase C. Ingenane has shown a degree of specificity in its cytotoxic action against leukemia cells and appears to be effective in small doses by in vitro studies.
The use of Euphorbia peplus in the treatment of basal cell carcinomas has also focused on ingenane. Topical applications of the diterpene ester three times daily have produced statistically significant levels of clearance in affected regions. Several trials for the use of the chemical in the treatment of non-malignant actinic keratosis or sunspots have also shown substantial degrees of improvement in many patients. Although there have not been extensive studies as of 2011 on the use of Euphorbia peplus in the treatment of warts, its historical use and success in the treatment of similar conditions suggests that it is worthy of investigation.
Fortunately, Euphorbia peplus is a common crop weed and invasive species in many parts of Europe, Asia, North America and Oceania. It grows readily in areas with low annual rainfall and poor soil quality, making it relatively inexpensive to cultivate or collect in the wild. The plant itself is between 3 and 10 inches (7.62 and 25.4 cm) in height and possesses smooth, hairless, latex-filled stems as well as the kidney-shaped thorned glands typical to members of the Euphoriacae family. Care should be taken when harvesting Euphorbia peplus, as the plant produces copius amounts of latex when damaged. This latex, while supposedly useful for the treatment of diseased tissue, can be toxic when it comes into contact with healthy skin.