In the early 1990s, certain forest shrubs of the Piperaceae, indigenous to the humid forests of Central America and Greater Amazonia, were found to contain high levels of safrole in their leaves. The Brazilian Amazon contains a wide variety of Piper species but attention had focused on P. hispidinervum and P. callosum, two species with high safrole content. Subsequently, P. callosum has been dropped in the research work in favor of the more promising P. hispidinervum. This effort was carried out by Museu Paraense Emilio Goeldi in Belém in collaboration with the Center for Agroforestry Research (CPAF-EMBRAPA) in Acre.
Piper hispidinervum known as "pimenta-longa" in Brazil, has been described by Yunker (1972). It is a nodose, branching shrub with rather slender upper internodes, somewhat angular, mostly 1–3 cm long, glabrous or very sparsely pubescent, somewhat glandular dotted. Leaves are oblong-lanceolate or elliptic-oblong, with attenuately acuminate apex and inequilateral base. This species resembles Piper aduncum L. to some extent but differs in its scarcely scabrous leaves, glabrous stem, and short peduncle (Yunker 1972). Coppen (1995) suggests that this species is distributed throughout South America, and is especially prominent in the state of Acre in Brazil and may extend into Amazonas.
The species is most frequently found on degraded forest, bordering primary forest or farm land where it occurs as a colonizing "weed," either as a pure stand or along with other Piper species. On natural sites, plants develop initially into bushes and at an early stage they appear to inhibit growth of competing vegetation. As the plants age they become more tree-like, up to 10 m tall.