African Milkbush, Pencil Cactus, Milk Bush

Euphorbia tirucalli

Physical Characteristics

Euphorbia tirucalli is an evergreen Shrub growing to 5 m (16ft) by 5 m (16ft) at a slow rate. See above for USDA hardiness. It is hardy to UK zone 10 and is frost tender. The flowers are pollinated by Insects. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid, very alkaline and saline soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry or moist soil and can tolerate drought. The plant can tolerates strong winds but not maritime exposure.

Distribution

Dry regions of tropical Africa, though widely grown and naturalised in many areas of the tropics.

Habitats

Edible Uses

Possible? but currently no data

Medicinal Uses

Antiasthmatic Antidote Antihaemorrhoidal Antirheumatic Antitumor Cancer Emetic Epilepsy Laxative Odontalgic Parasiticide Poultice Purgative Rubefacient Skin Stimulant Stings Vesicant Caution should be observed in making medicinal preparations of this plant due to its high toxicity[ 303 ]. Anecdotal evidence suggests that the risks of a lethal overdose are high, particularly when treating children[ 299 ]. Various studies have shown the presence of a range of active compounds in the plant:- Euphorbon, which is isolated from the needles, contains 4% caoutchouc[ 360 ]. The latex yielded 75 to 82 percent resin, and 14 to 15 percent caoutchouc[ 360 ]. The latex is rich in terpenes, including ingenol and phorbol esters[ 360 ]. The latter, which is highly irritating, has been shown to be tumour-promoting[ 360 ]. Six terpenes have been isolated from the plant:- cyclotirucaneol; cycloeuphordenol; tirucalicine; tirucaligine; euphorginol; and euphorcinol[ 360 ]. The latex showed great similarity in composition and activity to the highly poisonous croton seed oil from Croton tiglium[ 360 ]. The young branches can be roasted then chewed to relieve a sore throat[ 303 ]. Ash from the burned branches and stems is used to treat whooping cough[ 299 ]. The pulped twigs are applied externally to treat oedema of the legs[ 299 ]. Ash from the burned branches and stems is applied externally as a caustic to treat open abscesses[ 299 ]. Poultices from the stem are applied to heal broken bones[ 303 , 360 ]. Based on the Theory of Signatures, the jointed nature of the plant-stems lead to the use of the plant in SE Asia in a belief that it will assist the healing of broken bones[ 332 ]. A root and bud decoction is taken as a laxative, and to treat coughs and pectoral pain[ 299 ]. A poultice of the roots or stems has been applied to ulceration of the nose, haemorrhoids and swellings[ 303 , 360 ]. A root-decoction, combined with other drug-plants, is taken in in the treatment of schistosomiasis and gonorrhoea[ 299 , 332 ]. The boiled root juice acts as an emetic in cases of snake bite, and is also used for sterility in women[ 303 ]. Heated root scrapings, mixed with coconut oil, are applied externally to the stomach to relieve stomach-ache[ 303 , 360 ]. The caustic latex is vesicant, rubefacient and counter irritant. It is purgative in small doses, emetic in larger quantities[ 332 , 360 ]. Two or three drops at a time are given to adults with their food, whilst a dose of 3 - 4 drops is used as a purge to treat ascites and generalised oedemas[ 332 ]. The potent purgative and emetic properties are employed in Africa in order to treat stomach complaints, constipation, intestinal worms, headache, asthma, epilepsy and palpitations. A few drops of latex are reportedly sufficient to cause vomiting, and are taken in milk as an antidote to poisoning or snakebites[ 299 ]. Heated branches are chewed and the latex is swallowed to relieve a sore throat and dry cough, but also to induce labour during childbirth[ 299 ]. The latex is taken in the treatment of sexual impotence and sterility in East Africa, and elsewhere as a sexual stimulant. It is also said to promote breast enlargement[ 299 ]. The latex is used externally to treat skin-complaints, itches, insect bites, rheumatism, toothache, earache, to raise blisters on syphilitic nodes, and to remove warts, tumours, cancers, etc[ 299 , 332 , 360 ]. It is also used for wound healing[ 299 , 360 ]. The latex is widely used in Brazil to treat cancer, but in some areas where it is commonly used, tumours of the nose are prevalent and thought to be related to this use[ 299 ].

Known Hazards

The caustic, irritant sap contains a latex and is highly poisonous, causing severe injury to the eye, irritation and vesication from contact, emesis and purgation from ingestion[ 299 , 303 ]. Eye contact with the sap can cause blindness lasting several days[ 332 ]. The toxicity of the latex is considered seasonal or reduced in young plant parts, and young branches are even roasted and chewed[ 299 ]. The extracts of the plant contain a number of esters of the tetracyclic diterpenoid phorbol, many of which have been shown to act as tumour promoters (cocarcinogens). Their co-carcinogenic effect on lymphoblastoid cells poses a real threat in Africa where drinking water is drawn around the plants[ 303 ]. In East Africa the latex is commonly used as arrow poison and as an ingredient for bait to kill rodents and other wild animals; the pulped stems are thrown in water as fish poison[ 299 ]. In south-western DR Congo the latex has been used in high doses as a trial by ordeal poison; in various countries it is used as criminal poison[ 299 ]. (All parts of plant are poisonous if ingested Handling plant may cause skin irritation or allergic reaction )