After receiving admission to the Jesuit Order, João de Loureiro served as a missionary in Goa, capital of Portuguese India (3 years) and Macau (4 years). In 1742 he traveled to Cochinchina, remaining there for 35 years. Here he worked as a mathematician and naturalist for the king of Cochinchina, acquiring knowledge on the properties and uses of native medicinal plants. In 1777, he journeyed to Canton, in Bengal, returning to Lisbon four years later. During this period, the Captain Thomas Riddel gave Loureiro the books Systema Naturae, Genera Plantarum and Philosophia Botanica by Carl Linnaeus, which greatly influenced the Portuguese botanist.
The first 40 years he stayed in Vietnam, João de Loureiro was inventorying indigenous herbal remedies. His local garden contained 1,000 unique herbal species, making him one of the greatest botanist collectors of the 18th century.
João de Loureiro 1790, he published the book Flora Cochinchinensis sponsored by the Royal Portuguese Academy of Sciences. João de Loureiro has numerous species "loureiroi" dedicated to him, mostly plants but also the dinosaur Draconyx loureiroi in honour of his being the first Portuguese palaeontologist.
- Flora Cochinchinensis: sistens plantas in regno Cochinchina nascentes: quibus accedunt aliae observatae in Sinensi imperio, Africa orientali, Indiaeque locis variis: omnes dispositae secundum systema sexuale Linnaeanum
- Flora Cochinchinensis […] denuo in Germania edita, notes by Carl Ludwig Willdenow, 1793
- « On the nature and mode of production of Agallochum or aloes-wood », translated from Portuguese into English, in Tracts relative to botany, tr. from different languages, London, Phillips and Fardon […], 1805
- Pe. João de Loureiro : missionário e botânico by José Maria Braga, 1938.
- "NATURALMENTE scienza - Padre Loureiro e la flora della Cocincina".
- John W. O'Malley & al (1 January 1999). The Jesuits: Cultures, Sciences, and the Arts, 1540-1773, Volume 1. University of Toronto Press. ISBN 9780802042873.
- JSTOR, Loureiro and his botanical work by E.D. Merrill Proceedings of the American Philosophical Society Vol. 72, No. 4 (Apr., 1933), pp. 229-239
- Britt-Louise Gunnarsson (28 October 2011). Languages of Science in the Eighteenth Century. Walter de Gruyter. ISBN 9783110255065.
- Mateus, O. and Antunes, M.T., 2001, January. Draconyx loureiroi, a new camptosauridae (Dinosauria, Ornithopoda) from the Late Jurassic of Lourinhã, Portugal. In Annales de paléontologie (Vol. 87, No. 1, pp. 61-73). Elsevier Masson.
- International Plant Names Index. Lour.
- WorldCat Titles Pe. João de Loureiro, etc.