The present invention relates to plant cells and plants which synthesize an increased amount of hyaluronan, and to methods for preparing such plants, and also to methods for preparing hyaluronan with the aid of these plant cells or plants. Here, plant cells or genetically modified plants according to the invention have hyaluronan synthase activity and additionally an increased UDP-glucose dehydrogenase (UDP-Glc-DH) activity compared to wild-type plant cells or wild-type plants. The present invention furthermore relates to the use of plants having increased hyaluronan synthesis for preparing hyaluronan and food or feedstuff containing hyaluronan.