<![CDATA[Basil leaves (Ocimum basilicum L.) are herbal plants containing various secondary metabolite compounds such as alkaloids, flavonoids, saponins, and tannins that have the potential to have biological activity and toxic effects. Toxicity testing is needed as an initial stage to determine the level of safety and potential bioactivity of a natural ingredient. This study aims to determine the toxicity level of basil leaf ethanol extract using the Brine Shrimp Lethality Test (BSLT) method against Artemia salina Leach larvae. Basil leaf extract was obtained through the maceration method using 70% ethanol, then tested at concentrations of 20, 30, 40, 55, 75, and 95 ppm with three repetitions. The parameters observed were the number of larval deaths after 24 hours of treatment and analyzed using a probit test to determine the LC₅₀ value. The results showed that increasing the extract concentration caused an increase in the percentage of larval deaths, namely from 10–17% at a concentration of 20–40 ppm to 43–57% at a concentration of 55–95 ppm. The probit analysis yielded the equation Probit(p) = -1.624 + 0.020x with a significance value of p<0.05 and an LC₅₀ value of 80.58 ppm. This value indicates that the ethanol extract of basil leaves has toxic activity against Artemia salina larvae, as it is below the toxicity limit of 1000 ppm. Thus, the ethanol extract of basil leaves has the potential to be a source of bioactive compounds that can be further developed in pharmaceutical and health research.]]>
