In the present study, a new ceramide, namely 2 S, 3 R-4 E, 8 E-2-(heptadecanoylamino)-heptadeca-4, 8-diene-1, 3-diol ( 1), along with four known steroids, including 24-methylcholesta-5, 24(28)-diene-3 β-ol ( 2), 24-methylcholesta-5, 24(28)-diene-3 β-acetate ( 3), 4-methyl-24-methylcholesta- 22-ene-3-ol ( 4), and cholesterol, was isolated and characterized from CH 2Cl 2/MeOH extract of Cespitularia stolonifera. A new acetate derivative of compound 1, termed 2 S, 3 R-4 E, 8 E-2-(heptadecanoylamino)-heptadeca-4, 8-diene-1, 3-diacetate ( 1a), was also prepared in the present study. All the structures were established on the basis of modern spectroscopic techniques, including FT-IR, 1D, 2D-NMR, HRESI-MS, and GC-MS, in addition of chemical methods. (–)-Alloaromadendren, ledane, (1)-alloaromadendren oxide, isoaromadendrene epoxide and (–)-caryophellen oxide were identified from the n-hexane fraction using GC-MS. The extract and the two ceramides ( 1) and ( 1a) exhibited significant cytotoxic activity against lung cancer A549 cells, while the extract and the two steroids ( 2) and ( 3) exhibited significant cytotoxic activity against breast cancer MCF-7 cells. The CH 2Cl 2/MeOH extract exhibited significant antiulcer activity in both ethanol and acetic acid induced ulcer models in rats, as evidenced by histopathological, histochemical, and biochemical examinations.