About 20 quinolizidine alkaloids were identified inGenista acanthoclada by capillary GLC and GLC-MS, such as sparteine, 11,12-dehy-drosparteine, retamine,N-methylcytisine, cytisine, 17-oxosparteine, lupanine,α-isolupanine, 5,6-dehydrolupanine, 10-oxosparteine,N-carbomethoxycytisine, 17-oxoretamine,N-formylcytisine,N-acetylcytisine, and anagyrine. Its phloem-feeding holoparasiteCuscuta palaestina contained alkaloids too, such as sparteine, 11,12-dehydrosparteine, retamine,N-methylcytisine, cytisine, 17-oxosparteine, lupanine,N-carbomethoxycytisine, and anagyrine. Whereas sparteine, retamine, 17-oxosparteine, and cytisine are the main alkaloids ofG. acanthoclada, lupanine, cytisine,N-methylcytisine, and anagyrine are abundant and enriched inC. palaestina. Since these alkaloids figure as antiherbivoral chemical defense compounds inGenista, it is assumed that the parasite can exploit the acquired allelochemicals for its own protection.