The activity guided fractionation of the Clausena harmandiana root extracts led to the isolation of a coumarin, a ferulate, and eight carbazoles. This is the first report of the isolation of compounds 2-4 and 6-10 from this species, and this is the first time 10 was isolated from this genus. Compound 4 showed strong cytotoxicity against NCI-H187 cells with an IC(50) value of 1.63 microg/mL. Compound 5 demonstrated strong cytotoxicity against MCF-7 and KB cell lines with IC50 values of 2.21 and 1.74 microg/mL, respectively. Compounds 3 and 4 exhibited moderate cytotoxicity against the MCF-7 cell line, and 8 showed moderate cytotoxicity against NCIH187 and KB cell lines. Compounds 3 and 5 showed antiplasmodial activity with IC(50) values of 3.27 and 2.94 microg/mL, respectively.