Ten sesquiterpene lactones and one sesquiterpene isolated from Tanacetum praeteritum subsp. praeteritum: 1 alpha, 6 alpha -dihydroxyisocostic acid methyl ester (2), 1 alpha-hydroxy-1-deoxoarglanine (3), douglanin (5), santamarin (6), reynosin (7), 1-epitatridin B (8), ludovicin A (10), armexin (12), armefolin (13), armexifolin (14), and 3 alpha-hydroxyreynosin (15) were tested against the human lung carcinoma cell line GLC4 and the colorectal cancer cell line COLO 320 as well as against the bacteria Bacillus subtilis, Staphylococcus aureus, Proteus mirabilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus, beta-hemolytic Streptococcus, and the yeast Candida albicans. In addition, two germacranolides tatridin A (16) and tamirin (17) were included in the study. All compounds showed cytotoxic activity (IC50 = 124 microM) but most of them were not effective in the antimicrobial tests.