Guerrero, Leon (1853-1935), was a Filipino pharmacist and botanist who earned the title “Father of Philippine Botany” in 1935. He was the first Filipino in the field of pharmacognosy, the study of the sources, physical characteristics, composition, uses, and doses of drugs. Guerrero was also a supporter of the struggle for Philippine independence and a representative in the first Philippine assembly.
In 1881, Guerrero worked as a pharmacist with the Spanish corps in Zamboanga. He then went to San Juan de Dios Naval Hospital in Cavite, where he was in charge of pharmaceutical services. He opened his own pharmacy in Binondo in 1883. In 1887, Guerrero was appointed professor of pharmacy at the University of Santo Tomas, where he taught until his death.
Guerrero worked as a teacher at the Literary and Scientific University of the Philippines, established at Malolos in Bulacan by the Filipino revolutionary Emilio Aguinaldo in 1898. After the capture of Malolos by the Americans, the university moved to Tarlac. Guerrero founded the faculty of pharmacy at the Liceo de Manila (Lyceum of Manila) and was its first president, serving from 1900 to 1903. He served as botanist at the Bureau of Science in Manila from 1916 to 1933, becoming chief botanist in 1926.
In the early 1900’s, Guerrero conducted research into Philippine medicinal plants. He found that many drugs from native medicinal plants cured a range of illnesses, in many cases better than manufactured medicines could. In 1918, he wrote a study on 174 types of medicinal plants that could be used in place of synthetic (laboratory-made) drugs. He attended the first pan-Pacific science congress in Honolulu, Hawaii, in 1920. There he delivered a paper “Las Plantas Medicinales Utilizadas por los Filipinos” (“The Uses of Medicinal Plants for the Philippines”). He created an alternative to gunpowder that was used in the Filipino-American War (1899-1902) when gunpowder supplies ran out.
Guerrero was also involved in politics. He was a representative of the province of Surigo in the revolutionary government in 1898. In 1907, he represented the second district of Bulacan at the first Philippine Assembly.
Leon Maria Leogardo Guerrero was born in 1853 in Manila and educated at the Ateneo Municipal and the University of Santo Tomas. In 1888, he was admitted to the Sociedad Real de Historia Natural (Spanish Royal Society of Natural History). He was the first Filipino to become a member of the society. In 1888, he was appointed perito quimico (chemical expert) by the Real Audiencia (Supreme Court). He became a member of Junta de Sanidad de Manila (Manila Public Health Committee) in 1889. Several plants, including the Ilex guerreroii, are named in his honor.
