Chemical investigation of the soft coral Cladiella hirsuta, collected off the coast of Penghu Islands, has led to the isolation of natural products including ten new compounds hirsutalins A-D (1, 2, 3, 5) and hirsutosterols A-F (6, 7, 8, 9, 10, 11), and one known compound 3-butanoyloxycladiell-11(17)-en-6,7-diol (4). All of the chemical structures were established by detailed spectral data analysis (NMR, IR, MS) and by comparison of the spectral data with those of the related known compounds. The absolute structure of compound 1 was determined applying a modified Mosher¡¦s method. On the part of the cytotoxicity assay with six human cancer cell lines, HepG2 (liver cancer cell), Hep3B (liver cancer cell), Ca9-22 (mouth cavity cancer cell), A549 (lung cancer cell), MCF7 (breast cancer cell) and MDA-MB-231 (breast cancer cell), compound 5 showed the significant cytotoxicity against the cancer cell line HepG2; compound 7 showed the moderate cytotoxicity against all of the above cancer cell lines; compounds 6, 8 and 10 also showed the moderate cytotoxicity against two of them, Hep3B and Ca9-22. The products 6a and 7a , obtained by hydorlysis of 6 and 7, respectively, did not show obvious difference in cytotoxity by comparison of the IC50 values of compounds 6 and 7. On the part of anti-inflammation assay, compound 2 showed the effectively inhibiting activity against the induced iNOS and COX-2 proteins. Compound 3 showed nearly the same activity against the induced iNOS protein as that of 2.