Previous chemical work on the root bark of Clausena harmundiana Pierre (Rutaceae), a species reputedly used in folk medicine for stomach ache and fever, revealed the presence of five coumarins and one carbazole (heptaphylline). Further investigation of this plant resulted in the isolation of two novel 7-methoxycarbazole alkaloids, 2-hydroxy-3-formyl-7-methoxycarbazole and 7-methoxyheptaphylline. Their structures were elucidated using nmr, ir, and uv spectral data, confirming the positions of functional groups. Compound 1 (2-hydroxy-3-formyl-7-methoxycarbazole) was toxic to brine shrimp with an LC50 value of 35.1 ppm and a 95% confidence interval of 21.2-51.4 ppm, while compound 2 had an LC50 value >500 ppm. Both compounds were inactive on 9PS with ED50 values >10 µg/ml but slightly active in 9KB, KBMRI, A-549, and HT-29 cell lines, with compound 2 showing stronger activity. This paper describes the structural elucidation and bioactivity of these two new 7-methoxycarbazole alkaloids.