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(Caltrop or Creosote Bush family)


240 species in 25 genera are found in tropical and subtropical regions.

[Summary yet to be added]

Balanites Delile

Some authorities classify the genus in its own family, namely the Balanitaceae. It has also previously been classified in the Simaroubaceae.

Mechanical injury can result from these exceedingly spiny shrubs and trees of African bushland (Verdcourt & Trump 1969). The Masai of southern Africa used the thorns to pierce earlobes of children (Watt & Breyer-Brandwijk 1962).

Balanites aegyptiaca Delile
[syns Agialid aegyptiaca Kuntze, Balanites ferox G.Don, Ximenia aegyptiaca L.]
Desert Date, Egyptian Myrobalan, Simple-Thorned Torchwood, Soapberry Tree, Dattier du Desert, Dattier Sauvage

This species grows to form a small, spiny tree (Chopra et al. 1960). The spiny branches are used to fence cattle pens. Its spines may be 3 in [= 8 cm] long (Irvine 1961).

A toothpaste made of the bark caused erosive cheilitis. A patch test with the bark of the plant was negative, but strongly positive when mixed with the saliva of the patient (Strobel et al. 1978).

Phytochemical investigation of the bark has demonstrated the presence of the furanocoumarin bergapten (Seida et al. 1981). This renders the species potentially capable of inducing photoirritant dermatitis.

Balanites maughamii Sprague
[syn. Balanites dawei Sprague]
Green Thorn, Manduro, Y-Thorned Torchwood

[Information available but not yet included in database]

Balanites wilsoniana Dawe & Sprague

Menninger (1967) provides a photograph of the thorny trunk of this species.

Bulnesia arborea Engl.
[syns Guaiacum arboreum DC., Zygophyllum arboreum Jacq.]

This species provides timber known as Maracaibo lignum-vitae or verawood. The sawdust of Guaiacum arboreum caused sneezing and was called in French pique-niz (Guibort 1849).

Guaiacum officinale L.
Lignum Vitae

This species yields lignum vitae wood from which is obtained the medicinal resin guaiacum. The heartwood has an aromatic and irritating taste. The wood is used to make bowling woods and brush-backs, etc. Frei (1932) described a case of dermatitis which began around a minor finger wound contaminated with lignum vitae sawdust, and spread to the hands and arms. Patch tests to the sawdust gave positive reactions negative to some other woods and in controls. A case of contact dermatitis from application of Tincture of Guaicum was reported by White (1897). Guaicol derived from guaiacum has irritant properties (Greenberg and Lester 1954). The resin of the wood yields guaiaretic acid. Sensitivity to nordihydroguaiaretic acid is noted under Larrea.

Guaiacum sanctum L.
Lignum Sanctum

This species has properties similar to those of Guaiacum officinale. Oil of Guaiac wood is derived from Bulnesia (Greenberg and Lester 1954).

Kallstroemia maxima Wight & Arn.
[syn. Tribulus maximus L.]
Greater Caltrop

In an investigation of "weed dermatitis" in the southern United States, positive patch test reactions to an extract of this plant were observed in three of 50 consecutive patients tested (Shelmire 1939).

Larrea tridentata (DC.) Coville
[syns Covillea glutinosa Rydberg, Covillea tridentata Vail, Larrea divaricata Cav. subsp. tridentata Felger & C.H.Lowe, Larrea glutinosa Engelm., Neoschroetera tridentata Briq., Zygophyllum tridentatum Sessé & Moc. ex DC.]
Creosote Bush, Greasewood

A male developed dermatitis of the face, neck and hands a few hours after gathering the plant. A patch test to the leaf produced a positive reaction, negative in controls (Smith 1937). A man who was employed in preparing the wood for extraction of nordihydroguaiaretic acid developed dermatitis two weeks after he was first exposed (Weber 1953). Nordihydroguaiaretic acid, used as an antioxidant of fats, can cause allergic contact dermatitis (Jorgenson and Hjorth 1970, Hjorth and Roed-Petersen 1976).

Dorsey (1962) was probably referring to this species when he noted that he had heard of a case of contact dermatitis caused by greasewood. However, he may instead have been referring either to Sarcobatus vermiculatus Torr. (fam. Chenopodiaceae) or to Adenostoma fasciculatum Hook. & Arn. (fam. Rosaceae) as they are both also colloquially named greasewood.

Dictamnus albus L. in the family Rutaceae is also known colloquially as creosote bush.

This common native shrub of the deserts of the south-western United States is also cultivated. A gummy secretion makes the leaves look varnished and imparts a distinctive creosote-like odour, especially after rain. A tea is made from the root (Reemtsa and Maloney 1974).

Tribulus L.

20 species are found in tropical and subtropical regions.

The mericarps have sharp rigid spines which can stick into the foot of an animal. The name caltrop refers to the form of the fruit and indicates an iron ball armed with sharp prongs used on the battlefield in former times to impede cavalry horses. Centaurea is also known as caltrop.

Tribulus cistoides L.

This native weed of Hawai‘i, known as carpet weed since it covers large areas, can cause mechanical injury to the hands and feet (Pope 1968).

Tribulus pterophorus C.Presl

This species was listed by Steyn (1934) as a possible cause of tribulosis or geeldikkop in sheep. See Tribulus terrestris L. below.

Tribulus terrestris L.
Puncture Vine, Caltrop, Calthrops, Bullhead, Devil's Thorn, Cathead, Goathead, Mexican Sandbur, Texas Sandbur

Aplin (1976) notes that this species bears spiny fruit (burrs). The dried fruit is pernicious to the horse, for when the thorn enters the hoof, it completely rots the frog, crippling the horse (Maiden 1895). Gardner & Bennetts (1956) provide drawings of the ferociously spiny burr.

In traditional Chinese medicine, this plant is the source of a crude drug known as bai ji li (白蒺藜). A decoction of the shoots is used in scaly and scabious skin diseases (Stuart 1911).

This plant is the cause of tribulosis or geeldikkop (literally, "yellow big-head") in sheep that have eaten the plant. Tribulosis is a photodermatitis (Steyn 1934, Watt & Breyer-Brandwijk 1962). The toxic principles of the plant cause liver damage and accumulation of phylloerythrin in the blood. Phylloerythrin, which is a breakdown product of chlorophyll, acts as a photosensitising agent. A suggestion of photodermatitis in man from the plant (Mathews 1937) lacks confirmation.

For homicidal purposes, the poisonous juice of Acokanthera venenata is smeared on a suitable prickly fruit such as that of Tribulus terrestris and strewn on a path which is likely to be used by the victim (Watt & Breyer-Brandwijk 1962).

Tribulus terrestris L. var. orientalis Beck
[syns Tribulus lanuginosus L. var. orientalis M.P.Nayar & G.S.Giri, Tribulus orientalis A.Kern.]

[Information available but not yet included in database]

Tribulus zeyheri Sond.

This species was listed by Steyn (1934) as a possible cause of tribulosis or geeldikkop in sheep. See Tribulus terrestris L. above.


  • Aplin TEH (1976) Poisonous garden plants and other plants harmful to man in Australia. Western Australian Department of Agriculture. Bulletin 3964 [url] [url-2]
  • Dorsey CS (1962) Plant dermatitis in California. California Medicine 96(6): 412-413 [url] [url-2] [pmid]
  • Frei (1932) Pockholzekzem infolge Sensibilisierung nach Trauma. Zentralblatt für Haut- und Geschlechtskrankheiten 41(1/2): 29
  • Gardner CA, Bennetts HW (1956) The Toxic Plants of Western Australia. Perth: West Australian Newspapers [doi] [WorldCat] [url] [url-2]
  • Greenberg LA, Lester D (1954) Handbook of Cosmetic Materials. Their properties, uses, and toxic and dermatologic actions. With a bibliography of over 2,500 titles. New York: Interscience Publishers [doi] [WorldCat] [url] [url-2]
  • Guibort, M.J.-B.G. (1849) Histoire Naturelle des Drigues Simples. Paris, Bailliere. Cited by Woods and Calnan (1976).
  • Hjorth, N. and Roed-Petersen, J. (1976) Contact dermatitis from antioxidants. Hidden sensitizers in topical medications and foods. Brit. J. Derm. 94: 233.
  • Irvine FR (1961) Woody Plants of Ghana. With special reference to their uses. London: Oxford University Press [doi] [WorldCat] [url] [url-2]
  • Jorgensen, G. and Hjorth, N. (1970) Dermatitis from nordihydroguaiaretic acid, an antioxidant in fats. Contact Dermatitis Newsletter (7): 151.
  • Maiden JH (1895) The weeds of New South Wales. Supplementary notes. No. 1. Agricultural Gazette of New South Wales 6(10): 671-678
  • Mathews, F.P. (1937) Photosensitisation and the photodynamic diseases of man and the lower animals. Arch. Path. 23: 399.
  • Menninger EA (1967) Fantastic Trees. New York: Viking Press [WorldCat] [url]
  • Pope, W.T. (1968) Manual of Wayside Plants of Hawaii. Rutland, Vermont. Charles E. Tuttle Co.
  • Reemtsma, K. and Maloney, J.V. (1974) The economics of instant medical news. New Engl. J. Med. 290: 439.
  • Schwartz L, Tulipan L, Birmingham DJ (1957) Irritant plants and woods. In: Occupational Diseases of the Skin. 3rd edn, pp. 636-672. London: Henry Kimpton [doi] [WorldCat] [url] [url-2]
  • Seida AA, Kinghorn AD, Cordell GA and Farnsworth NR (1981) Isolation of bergapten and marmesin from Balanites aegyptica. Journal of Medicinal Plant Research 43: 92-103.
  • Senear FE (1933) Dermatitis due to woods. Journal of the American Medical Association 101(20): 1527-1532 & unpubl. table accompanying reprints [doi] [url] [url-2]
  • Shelmire, B. (1939) Contact dermatitis from weeds; patch testing with their oleoresins. J. Am. Med. Ass. 113: 1085.
  • Smith, L.M. (1937) Dermatitis caused by creosote bush. J. Allergy 8: 187.
  • Steyn DG (1934) The Toxicology of Plants in South Africa together with a consideration of poisonous foodstuffs and fungi. South Africa: Central News Agency
  • Strobel M et al. (1978) Les dermites de contact d'origine végétale. Bull. Soc. Méd. Afr. Noire Lang. Fr. 23: 124.
  • Chopra IC, Abrol BK, Handa KL (1960) Part One. With particular reference to the botanical aspects. In: Arid Zone Research — XIII. Medicinal Plants of the Arid Zones, pp. 11-53. Paris: United Nations Educational, Scientific and Cultural Organization [WorldCat] [url]
  • Stuart GA (1911) Chinese Materia Medica. Vegetable Kingdom. Extensively revised from Dr. F. Porter Smith's work. Shanghai: American Presbyterian Mission Press [doi] [WorldCat] [url] [url-2]
  • Verdcourt B, Trump EC (1969) Common Poisonous Plants of East Africa. London: Collins [WorldCat] [url]
  • Watt JM, Breyer-Brandwijk MG (1962) The Medicinal and Poisonous Plants of Southern and Eastern Africa. Being an account of their medicinal and other uses, chemical composition, pharmacological effects and toxicology in man and animal, 2nd edn. Edinburgh: E & S Livingstone [doi] [WorldCat] [url] [url-2]
  • Weber, L.F. (1953) Dermatitis venenata from native woods. Archs Derm. Syph. 67: 388.
  • White, J.C. (1897) Notes on dermatitis venenata. Boston Med. Surg. J. 136: 77.
  • Woods B, Calnan CD (1976) Toxic woods. British Journal of Dermatology 95(Suppl 13): 1-97 [doi] [url] [url-2] [pmid]
  • Zafiropoulo A, Audibert A, Charpin J (1968) A propos des accidents dus a la manipulation des bois exotiques. [Accidents due to the handling of exotic woods]. Revue Française d'Allergie 8(3): 155-171 [doi] [url] [pmid]

Richard J. Schmidt

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