Poinsettia

Euphorbia pulcherrima is kept worldwide as an Advent plant and winter ornamental indoors. Outside the temperate zone it is a shrub or small tree up to 4 m. As a potted plant during the pre-Christmas season it requires bright positions (no direct sun), temperatures above 15 °C, and protection from draughts. The intensely red bracts — not the true flowers — are responsible for the ornamental effect.

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In Aztec folk medicine (Nahuatl: Cuetlaxochitl), the milky latex was applied to burns and inflammatory skin irritations. The Aztecs also used the leaves as a dressing material and for haemostasis. This application is documented through ethnobotanical sources. Due to diterpene esters in the latex, the milky sap can itself cause contact dermatitis in sensitive skin — therefore only with caution and after a skin tolerance test.

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Historically, diluted latex from poinsettia was used in Mexico as a remedy for warts: a few drops applied directly to the wart. The caustic action of diterpene esters is said to destroy the wart tissue. Comparable wart remedies are also obtained from other Euphorbia species (E. peplus — petty spurge). This application is NOT recommended for self-prepared extracts; avoid contact with healthy skin and eyes.

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In some regions of Mexico and Central America, leaf infusions of poinsettia were used in folk medicine for fever. This internal application is NOT recommended and is poorly documented historically. The latex can cause nausea and mucosal irritation upon oral ingestion. Toxicological investigations (Winek et al. 1978, Runyon 1980) show the plant is less toxic than historically feared, but internal application remains unjustifiable without a benefit-risk evaluation.

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In Mexican folk medicine, poinsettia leaves were added to bath water for fever-reducing sit-baths or full baths. Use as a foot bath or diluted body bath is considered less problematic than direct latex contact, since water-soluble constituents contain fewer diterpene esters than pure latex. Nevertheless: test tolerance in sensitive skin.

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TOXICITY MYTH CORRECTED: The widespread myth that poinsettia is lethally toxic to humans is scientifically refuted. Clinical studies (Winek et al. 1978, Runyon 1980) show that even ingestion of large quantities of leaves and stems causes no lethal toxicity in rats. Poison control centre data demonstrate that contact exposure or swallowing small amounts typically causes only mild gastrointestinal irritation and/or skin redness. The latex can cause contact dermatitis and eye irritation — but NO systemic poisoning under normal household conditions.

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