The aerial parts of Zanthoxylum ovalifolium ( Rutaceae) have yielded the two novel benzo[ c]phenanthridine alkaloids terihanine (8-demethylnitidine) and isoterihanine (9-demethylnitidine) together with nitidine, the unusual furoquinoline 5-methoxydictamnine, canthin-6-one and several common furocoumarins. The finding of benzo[ c] phenanthridine and furoquinoline alkaloids in Australian material of this species confirms its chemical homogeneity throughout its range from India to Australia.