Steviolbioside, 13-[(2-O-b-D-glucopyranosyl-b-D-glucopyrano syl)oxy]kaur-16-en-18-oic acid, is a bioactive nature sweetener, which is rare in Stevia rebaudiana leaves. It is also the main metabolite of the star sweetener rebaudioside A and its analogue stevioside, yet it can be used as an intermediate of some medications, which makes steviolbioside an important reagent in medical science in addition to a food additive. Steviolbioside has antituberculosis activity. Steviolbioside has been used in trials studying the treatment of HIV-1 Infection. Except for its antihyperglycaemic and antihypertensive effects, steviolbioside was found as a moderate antituberculosis activity against Mycobacterium tuberculosis strain H37RV in vitro (MIC = 3.75 ug/ml), compared to that of stevioside (MIC = 7.5 ug/ml). The hydrolysis product steviolbioside presented higher cytoxicity on human normal cells (hepatocytes cell L02 and intestinal epithelial cell T84) than did its starting material stevioside. e. Compared to the typical chemotherapy agent, 5-fluorouracil (5-FU), steviolbioside has a much lower cytotoxic effect on all assayed human normal cells, but it presented notable inhibition on Hep3B, human breast cancer cell MDA-MB-231 and human pancreatic cancer cell BxPC-3. The inhibition rate on MDA-MB-231 of steviolbioside was 50% of that of 5-FU, which implies a hopeful potential remedy for human breast cancer.