We examined the effects of extracts and volatiles from garlic on breaking bud dormancy in 'Muscat of Alexandria' and 'Kyoho' grapevine cuttings. When commercial garlic oil was applied to the distal cross-sectional cut surface of cuttings, it greatly promoted a steady rate of budbreak, but slurried commercial garlic powder or lanolin paste containing freeze-dried garlic extracts had little or no effect. Application of both supernatants and precipitates of centrifuged boiled grated garlic had little effect, but exposure of cuttings to volatiles from grated garlic and commercial garlic oil promoted budbreak. These observations indicate that some volatile compounds in garlic are responsible for breaking bud dormancy in grapevines. Garlic volatiles were most promotive during the deep dormant stage in November but least effective toward the end of dormancy.