Cecropia strigosa Trecul is a plant with biomedical potential due to its phytochemical properties. However, its use in practical applications requires prior evaluation of its safety profile. Objective: to determine the acute toxicity of the alcoholic and hydroalcoholic extract of leaves and bark of Cecropia strigosa Trecul in nauplii of Artemia franciscana. Methodology: Leaves and bark of C. strigosa Trecul were collected from healthy individuals, following ethical and sustainability procedures. The plant materials were dried and finely ground for subsequent extraction. The alcoholic and hydroalcoholic extracts were prepared using analytical grade ethanol and distilled water. A. franciscana eggs were incubated in 3% Instant Ocean solution until reaching the nauplius phase, which were exposed to concentrations of 10, 100 and 1000 ppm of each extract for 24 hours. Nauplii mortality was rec...