The term “cancer weed plant” is an informal designation for various plants, often stemming from traditional uses or anecdotal claims rather than scientific evidence. This article clarifies which plants are commonly associated with this term and addresses their claims, distinguishing between traditional practices and established scientific knowledge.
Common Plants Referred to as “Cancer Weed Plant”
Several plants are informally known as “cancer weed” due to their traditional medicinal uses or widespread presence. One prominent example is Euphorbia peplus, often called petty spurge, radium weed, or milkweed. This annual herb typically grows 5 to 30 centimeters tall with smooth stems and oval leaves, commonly found in gardens, cultivated land, and disturbed areas across Europe, North Africa, Western Asia, and widely naturalized elsewhere. Its milky sap is a distinctive feature.
Another plant associated with the term is Phyllanthus niruri, also known as “chanca piedra,” “stonebreaker,” or “seed-under-leaf.” This widespread tropical plant, belonging to the Phyllanthaceae family, grows about 50 to 70 centimeters tall and features thin, leaf-covered branches with small, pale green flowers and tiny fruits that grow beneath the leaves. It is prevalent in coastal areas from Texas through Mexico, Central America, and wide regions of South America.
Euphorbia hirta, sometimes called asthma-plant or hairy spurge, is another pantropical weed originating from tropical regions of the Americas. This hairy annual herb can reach up to 60 centimeters in height, featuring reddish or purple stems and ovate leaves often blotched with purple. It thrives in open grasslands, roadsides, and pathways, producing a distinctive milky sap. Elephantopus scaber, known as elephant’s foot or prickly elephant’s foot, is a perennial herbaceous plant growing 30 to 90 centimeters tall, with a rosette of basal leaves and white or pale lavender flowers. It is native to tropical and subtropical regions of Asia, Africa, and the Americas, often found in grasslands and disturbed habitats.
Traditional Uses and Unverified Claims
The “cancer weed” designation stems from historical and traditional medicinal practices, where plants were used for various ailments, including those perceived as cancerous growths. Euphorbia peplus, for instance, has a long history of use in traditional medicine, with its sap historically applied as a remedy for common skin lesions like warts, corns, and sunspots. In some traditional contexts, it was also used for conditions such as asthma, catarrh, and to reduce blood pressure.
Phyllanthus niruri has been widely used in traditional systems, particularly for kidney stones, earning it the name “stonebreaker” due to claims it helps prevent acidic kidney stones and increases urine flow. Traditional uses for Phyllanthus niruri include addressing jaundice, gonorrhea, and diabetes. The plant is also traditionally employed for liver conditions and digestive disorders.
Euphorbia hirta has been a staple in traditional herbal medicine across many cultures, notably for respiratory conditions like asthma, various skin ailments, and hypertension. In some regions, it is consumed as an herbal tea for fevers, including those associated with dengue and malaria. Elephantopus scaber has a long history in traditional medicine systems, with its leaves and roots used to prepare remedies for respiratory conditions, digestive disorders, skin diseases, and inflammation. It has also been traditionally used as a diuretic and to promote wound healing. These traditional applications highlight a belief in the therapeutic properties of these plants, though such claims predate modern scientific verification.
Scientific Perspective and Safety Concerns
Despite traditional uses, scientific evidence for “cancer weed plants” efficacy against cancer in humans is limited. For Euphorbia peplus, its sap contains ingenol mebutate, a diterpene ester, which has shown activity against rapidly replicating human tissue and is approved in a pharmaceutical-grade gel for treating actinic keratosis (a form of non-melanoma skin cancer). This does not extend to systemic cancer treatment. Clinical studies on E. peplus sap for non-melanoma skin cancers have shown positive responses for superficial lesions, but these are specific topical applications and not a general cure for internal cancers. The sap is toxic and can cause skin irritation or dermatitis upon contact.
For Phyllanthus niruri, while it contains various phytochemicals, rigorous clinical trials in humans conclusively proving its efficacy against cancer are lacking. Research has primarily focused on its effects on kidney stones and liver conditions, with some studies on hepatitis B. However, the effectiveness for these conditions still requires more robust scientific backing. High doses of Phyllanthus niruri are toxic.
Euphorbia hirta has been studied for its phytochemical constituents and pharmacological properties, but comprehensive clinical evidence supporting its use as an anticancer agent in humans is not established. Elephantopus scaber has also been investigated for its compounds, but conclusive scientific data on its anticancer properties through human clinical trials remains insufficient. Self-medicating with these plants without professional medical guidance can be dangerous. Relying on them as a primary treatment for cancer can delay or replace effective, evidence-based medical care, potentially leading to adverse health outcomes. Risks include toxicity, unpredictable side effects, and negative interactions with prescription medications.
Managing “Cancer Weed Plant” in Your Environment
When informal “cancer weed plants” appear as unwanted plants in a garden or landscape, several non-toxic management strategies can be employed. Manual removal is an effective method for controlling individual plants or small infestations. Pulling them by hand, especially when the soil is moist, helps ensure the removal of the entire root system, reducing the likelihood of regrowth.
Applying a layer of organic mulch, such as wood chips or straw, can suppress weed growth by blocking sunlight and inhibiting seed germination. Mulch also helps retain soil moisture and regulate soil temperature, creating less favorable conditions for weed establishment. Proper garden practices, including adequate spacing between desirable plants and maintaining healthy soil, can deter weed proliferation. Ensuring that garden beds are not left bare allows cultivated plants to outcompete weeds for resources.