Many epidemiological studies have revealed that there is a strong correlation between consumption of polyphenol-rich foods or beverages and the prevention of certain diseases such as cancers, cardiovascular diseases and aging. Phenolic compounds are abundant in all plants, therefore they form an integral part of the human diet. Salvia species, commonly known as sage, have been used since ancient times for more than 60 different ailments ranging from aches to epilepsy. There are around 900 species of Salvia, 95 of which are represented in Turkey including Salvia fruticosa. In this study, DPPH● and ABTS● radicals scavenging activities, total phenolic and flavanoid contents of water extract of S. fruticosa was determined by spectrophotometrically. Rosmaniric acid, caffeic acid, gallic acid, syringic acid, quercetin and t-resveratrol contents of water extract of S. fruticosa were determined by using RP-HPLC. Cytotoxic effect of the extract on HT-29 adenocarcinoma cell lines was examined via XTT colorimetric and Trypan Dye Exclusion cell viability assay. Effects of the extract on the expression of phase I and phase II detoxcification enzymes in HT-29 cell line were investigated with q-RT-PCR technique. Turkish endemic sage, S. fruticosa, is reported to be a promising medicinal plant, it has the potential to be used as adjuvant with chemoterapeutic agents to overcome the drug resistance occuring during chemotherapy. Further investigations are ungoing to reveal its bioactive components and their beneficial activities in biological systems.