Chelidonium majus is an important medical plant used in traditional and folk medicine throughout the world but also a common weed in nature and around human habitats. C. majus extracts exhibit antiviral, antitumour, antimicrobial and anti-inflammatory effects. The present study is focused on the investigation of extracts from C. majus against Xanthomonas vesicatoria and Xanthomonas gardneri causing bacterial spot of tomato in Bulgaria as an alternative means of control. The obtained extracts possessed antibacterial activity against the pathogens. One of the fractions showed the best potential for control of bacterial spot of tomato.