Garlic (Allium Sativum L.) has long been a traditional herbal medicine. One of the main organosulfur compunds found in garlic is allicin, which is to have potential anticancer activity. This study aims to envestigate the cytotoxic effect of garlic extract on MCF-7 breast cancer cells. Extraction was carried out using the cold press method without solvents to maintain the integrity of the active compunds. The methods used in this study included organosulfur compound testing and analysis using Fourir Transform Infrared (FTIR) Spectroscopy. The spectral analysis showed an absorption peak at the fifth peak with a wavelength range of 1027,82 cm-1, indicating the presence of S=O functional group vibrations, which are charateristic of organosulfur compounds. The cytotoxic test was counducted in vitro using the MTT assay method with various concentrations of garlic extract: 100 µg/mL, 50 µg/mL, 25 µg/mL, 12,5 µg/mL, 6,25 µg/mL, and 3,125 µg/mL. The parameter used to measure cytotoxic activity was the IC50 value. The results showed that the IC50 value of the garlic extract was 757,888 µg/mL, which is categorized as weakly active. Therefore, it can be concluded that garlic extract contains organosulfur compunds identified through FTIR spectrum at the wavenumber 1027,82 cm-1 (S=O vibration), and it exhibits weak cytotoxic activity against MCF 7 breast cancer cells with an IC50 value of 757,888 µg/mL.