Abstract. Cytotoxic compounds are compounds that can damage cells, and can also be used to inhibit the growth of malignant tumor cells. Based on the study, it is stated that salam bark (Syzygium polyanthum (Wight) Walp.) contains flavonoid compounds, which are thought to have anticancer activity. This research was conducted to determine the cytotoxic activity of ethanol extract, water fraction, ethyl acetate fraction, and n-hexane fraction of salam bark based on LC50 value against Artemia franciscana Kellogg at various concentrations of 10 ppm, 50 ppm, 100 ppm, 250 ppm, 500 ppm, 750 ppm, and 1000 ppm. Cytotoxic effect from extract and each fraction was analyzed based on the mortality percentage of Artemia franciscana Kellogg and the LC50 value calculated by probit value method. Based on the result obtained, the LC50 extract value is 1532,85 ppm, the LC50 water fraction value is 593,34 ppm, the LC50 ethyl acetate fraction value is 1865,52 ppm, and the LC50 n-hexane value is 891,25 ppm. Based on the results, it can be concluded that the water fraction has a higher cytotoxic effect. Abstrak. Senyawa sitotoksik merupakan senyawa yang dapat merusak sel, serta dapat digunakan untuk menghambat pertumbuhan sel tumor ganas. Berdasarkan sebuah penelitian menyatakan bahwa kulit batang salam (Syzygium polyanthum (Wight) Walp.) mengandung senyawa flavonoid, yang diduga memiliki aktivitas sebagai antikanker. Penelitian ini dilakukan untuk mengetahui aktivitas sitotoksik dari ekstrak etanol, fraksi air, fraksi etil asetat, dan fraksi n-heksana kulit batang salam berdasarkan parameter nilai LC50 terhadap Artemia franciscana Kellogg menggunakan metode Brine Shrimp Lethality Test (BSLT), dengan variasi konsentrasi 10 ppm, 50 ppm, 100 ppm, 250 ppm, 500 ppm, 750 ppm, dan 1000 ppm. Efek sitotoksik dari ekstrak dan masing-masing fraksi dianalisis berdasarkan persentase mortalitas Artemia franciscana Kellogg dan nilai LC50 dihitung menggunakan metode nilai probit. Berdasarkan hasil penelitian diperoleh nilai LC50 ekstrak sebesar 1532,85 ppm, nilai LC50 fraksi air sebesar 593,34 ppm, nilai LC50 fraksi etil asetat sebesar 1865,52 ppm, dan nilai LC50 fraksi n-heksana sebesar 891,25 ppm. Berdasarkan hasil tersebut, dapat disimpulkan fraksi air memiliki efek sitotoksik yang lebih tinggi.