The effect of strigolactones on plants, which has been recently described as a new group of plant hormones, has not been fully characterized. Capparis spinosa L. callus formation using synthetic strigolactone GR24 (0.1 and 0.2 μM) alone or in combination with 1-naphthalene acetic acid (NAA) (2 mg / L) and 6-benzylaminopurine (BAP) (1 mg / L) and its effect on phenolic substance production were evaluated. 2 mg/L NAA+1 mg/L BAP+0.1 μM GR24 was the medium with the highest callus formation (60.3%) and callus fresh weight (120.8 mg). In the phytochemical analysis, the highest total flavonoid and phenolic substance and the highest rutin, quercetin, chlorogenic acid content were found in this application and their amounts increased at various rates compared to the control. Aromatic substances in caper calluses were grouped as sulfur compounds (66.97% -87.53%), aldehydes (4.88% -7.90%), ketones (0.34% -19.3%), hydrocarbons and derivatives (0.56%-5.8%), alcohols (% 1.62-6.08%), others (0.61% -2.37%) and their amounts varied at various hormone applications. When 0.1 μM GR24 was applied alone, the total sulfur compound in callus samples was 87.53% and the dominant substance was found to be methyl isothiocyanate.