The finds of remains of useful plants in archaeological objects were drawing attention already in the last century. However, it was not until after the World War II, in relation with renovation of historical cores of the towns, when a separate branch of the botany–archaeobotany constituted. In the Czech Republic it was E. Opravil who was the first to become engaged in a systematic archaeobotanical research at the beginning of the 60’s. All the vegetal remains–fruits and seeds on the first place as well as pollen grains from prehistoric times to the post-medieval period, are the subjects of archaeobotany. The medieval waste pits are the richest sources of the vegetal remains. They contain a lot of diasporas of cultural as well as wild plants. The remains of useful plants are an authentic document of the vegetal component of diet. Even though some vegetal species, such as for example garlic, onion or stalk-plants, about whose cultivation we are informed from literature, occur only seldom, there appeared also the species not mentioned in literature. All the basic cereals have been known in our country already since the early Middle Ages. Wheat (Triticum aestivum) and rye (Secale cereale), as well as millet (Panicum miliaceum) that, along with buckwheat (Fagopyrum esculentum), were replaced by potatoes in the modern times were the most important. Also leguminous plants were of great importance in the diet even though their charred seeds seldom preserved. Remains of oil plants such as hemp (Cannabis sativa), flax (Linum usitatissimum) and poppy (Papaver somniferum) preserved well. It was successfully proved that cucumber (Cucumis sativus), among other numerous kinds of vegetables, was introduced by the Slavs already in the 8th century in Moravia and in the 9th century in Bohemia. The assortment of fruit was rich–especially the assortment of cultivated fruit. Among the imported kinds of fruit the first place occupied figs (Ficus carica), from the numerous finds it can be said that they formed a common part of the diet. Among imported fruit and spices from the peak period of the Middle Ages we succeeded in finding a date-tree (Phoenix dactylifera), nutmeg tree (Myristica fragrans) and, by means of pollen analysis, maybe a clove tree (Eugenia caryophyllata).