Occurrence of rosmarinic acid and chlorogenic acid in the plant kingdom: Rosmarinic acid (RA) and chlorogenic acid (CA) are caffeic acid esters. They are widespread in the plant kingdom and presumably serve as defense substances. In the present study, more than 240 plant species have been examined for the occurrence of rosmarinic acid and chlorogenic acid. Several rosmarinic acid-containing species were detected. The presence of rosmarinic acid within the family Marantaceae was not known before. Rosmarinic acid has already been detected in hornworts, in ferns of the family Blechnaceae and in different species within the orders of the monocotyledonous plants (Alismatales, Liliales, Poales, Zingiberales) as well as in the rosids and asterids of the eudicotyledonous plants (Myrtales, Celastrales, Rosales, Cucurbitales, Malvales, Gentianales, Lamiales, Apiales, Asterales, Dipsacales). Only one proof of RA has been reported of the basal orders in the genus Chlorantus (Chloranthaceae, Chloranthales). Similarly, chlorogenic acid has also been detected in very different families and orders, however to a lesser extent in monocots. In this study, the RA- and CA-containing species from the present work were not necessarily classified as closely related families or orders. In the present study, RA was detected only in two species of the family Blechnaceae (Blechnum brasiliense and B. gibbum), but not in the other species of Blechnum, whereas CA was often found in the Blechnaceae. RA and CA were discovered in both the examined species of Canna. Within the family Marantaceae, RA could be isolated only from Maranta leuconeura, Maranta depressa and Thalia geniculata, and neither from any other of the four investigated species of Maranta nor from one of the seven additionally analyzed other genera of the family Marantaceae. The presence of CA and of RA was totally independent in the Marantaceae. Rutin has also been detected in Zingiberales, namely in Cannaceae, Lowiaceae, Marantaceae and Strelitziaceae. It is known that RA occurs throughout the Boraginaceae, which was confirmed in the present study, but it is interesting that the content of CA in the plants that contain high concentrations of RA was usually very low. The same applied to the Lamiaceae. Collinsonia canadensis contained the highest concentration of rosmarinic acid of all investigated RA-containing plant species (15.50% of the DW). Furthermore, for a long time RA was considered to be a characteristic compound of the subfamily Nepetoideae, which was supported by the present study. In Apiaceae, RA was isolated only from Astrantia major, whereas CA was found frequently in this family. In the Malvaceae, RA has previously been demonstrated and the present study confirmed this result. The occurrence of CA is totally independent in the family. It is striking that chlorogenic acid is more widespread in the plant kingdom than rosmarinic acid, since chlorogenic acid has been demonstrated in many families and orders in which rosmarinic acid has not been found. Phylogenetic studies are based on morphological and on molecular data, and it was interesting to find out whether RA and CA could be considered as chemotaxonomic markers: It becomes obvious that RA and CA are not suitable as chemotaxonomic markers since the compounds occur widely in the plant kingdom and are not consistent in different species of an order or different genera of a family or different families of an order. The occurrence of natural compounds in in vitro cultures of species of the Zingiberaceae: Callus cultures were established from Curcuma xanthorrhiza, Curcuma longa and Zingiber officinale on various growth media. The callus cultures were analyzed and examined for the presence of curcuminoids and gingerols. In addition, plant material was infected with Agrobacterium rhizogenes in order to achieve hairy root cultures. On the other hand, suspension cultures were established from the cell cultures and elicited with methyl jasmonate. All tests have shown negative results, gingerols or curcuminoids have not been detected.