Garlic (Allium sativum) is rich in organosulphur compounds, which are considered responsible for most of its beneficial physiological effects that reduce the risk of cardiovascular disease. Allicin (diallyl thiosulfinate), the main organosulfur compound, is produced from the amino acid alliin by alliinase when garlic is crushed. Allicin rapidly decomposes mainly to diallyl sulfide (DAS), diallyl disulfide (DADS), diallyl trisulfide (DATS), and ajoene. After consumption, neither allicin nor its metabolites have been found in blood or urine, indicating that these compounds are rapidly metabolized. We have recently shown that H2S reduces uterine contractility. We were therefore interested to investigate if garlic and its constituents could reduce contractility, with a long term goal of preventing preterm labour. Myometrial strips from term pregnant humanely killed rats were dissected, superfused with Krebs and the effects of adding for 15-30 mins, garlic powder,(Rajah brand) garlic oil ( Sigma, which contains 30-50 wt % DAS, 10-13 wt % DATS ) and DATS (Santa Cruz) were studied. The garlic powder studied from 0.01 to 1 mg/ml had little effect on contractions, although a significant decrease in amplitude was found at 0.7 mg/ml (73±6% versus 100% control, mean +sem, n=3). Garlic oil, at 1:1000, greatly reduced or abolished contractions. DATS dose dependently reduced uterine contractions, particularly their amplitude. Thus at 750 µM amplitude was significantly reduced to 77± 7%, n = 6, paired t-test. Our data suggest that the organosulphur compounds in garlic can inhibit uterine contractions. Given our earlier findings that H2S releasing compounds significantly reduce uterine contractions and Ca transients, we suggest that these effects of garlic organosulphur compounds will be via H2S production. These preliminary data suggest that garlic may be a useful supplement to help prevent preterm delivery.