[12][13][14][15] [1][ In its natural range along the dry coasts of southern Madagascar, Catharanthus roseus is considered weedy and invasive, often self-seeding prolifically in disturbed areas along roadsides and in fallow fields.

[16][17] It is also, however, widely cultivated and is naturalized in subtropical and tropical areas of the world such as Australia, Bangladesh, India, Malaysia, Pakistan, and the United States.

Numerous cultivars have been selected, for variation in flower colour (white, mauve, peach, scarlet, and reddish-orange), and also for tolerance of cooler growing conditions in temperate regions.

Conflict between historical indigenous use, and a patent from 2001 on C. roseus-derived drugs by western pharmaceutical companies, without compensation, has led to accusations of biopiracy.

[24] Vinblastine and vincristine, chemotherapy medications used to treat several types of cancers, are found in the plant[25][26][27][28] and are biosynthesised from the coupling of the alkaloids catharanthine and vindoline.

[29] The newer semi-synthetic chemotherapeutic agent vinorelbine, used in the treatment of non-small-cell lung cancer,[27][30] can be prepared either from vindoline and catharanthine[27][31] or from the vinca alkaloid leurosine,[32] in both cases via anhydrovinblastine.

[35] Treatment of the plant with phytohormones, such as salicylic acid[36] and methyl jasmonate,[37][38] have been shown to trigger defense mechanisms and overproduce downstream alkaloids.

[47] C. roseus can be extremely toxic if consumed orally by humans, and is cited (under its synonym Vinca rosea) in the Louisiana State Act 159.

On consumption, symptoms consist of mild stomach cramps, cardiac complications, hypotension, systematic paralysis eventually leading to death.