The aim of the study was to describe various classes of chemical substances found in plant that may pose a toxicological threat for pets. For each plant is described their toxic principles, the parts responsible for intoxication, clinical symptoms and recommended treatmants. For most of the poisoning caused by toxic houseplants treatment is supportive and symptomatic care. House and yard plants can be a potential source of companion animals poisoning, due to chemical substances in most of the plants, which can cause clinical symptoms in animals, if present in specific amounts. This thesis present plant families, genuses and species mostly present in households, for which there is scientific evidence on their toxic effect on animal organism. The following families are described: the lily family (lat. Liliaceae), the primrose family (lat. Primulaceae), the amaryllis family (lat. Amaryllidaceae), the arum family (lat. Araceae), the heath family (lat. Ericaceae), the spurges family (lat. Euphorbiaceae), the stonecrop family (lat. Crassulaceae), the dogbane family (lat. Apocynaceae), the araliaceae family (lat. Araliaceae), the yew family (lat. Taxaceae), the daisy family (lat. Asteraceae) and zamiaceae family (lat. Zamiaceae). Toxic mechanisms and suggested treatments are described for each plant. Moreover, case reports are described, which presents animal toxication with specific plant types.