Dumb canesDumb canes (DieffenbachiaDieffenbachia spp.) are perennial herbaceous plants nativeNative to the New World Tropics. Due to their dramatic and attractive foliar variegation, ability to tolerate low light, and ease of production, dumb canesDumb canes have been produced as potted ornamental foliage plantsOrnamental foliage plants (house plantsHouse plants) for interior plant scapingInterior plantscaping or grown as landscape plants in the shade in tropical and certain subtropical regions. DieffenbachiasDieffenbachia leavesLeaf are rich in calcium oxalate crystalsCalcium oxalate crystals including raphidesRaphides and drusesDruses. The release of the crystals, along with some proteolytic enzymes can cause a burning sensation and severe rash. If leavesLeaf or stems are ingested, it results in swelling of tongue, mouth, and throat and restricts normal speech, which is why it is known as dumb caneDumb canes . Despite these toxic effects, DieffenbachiaDieffenbachia has remained one of the most popular foliage plant genera since its introduction in the 1800s. This chapter is intended to introduce dieffenbachiasDieffenbachia as popular ornamental foliage plantsOrnamental foliage plants, their value and toxicity, and their production. An emphasis is placed on crop improvement including genetic resourcesGenetic resources, breedingBreeding objectives, and methods for developing new cultivarsCultivars. It is conceivable that with continuous efforts on geneticGenetic improvement, dieffenbachiaDieffenbachia cultivarsCultivars with novel foliar variegation and reduced toxicity will be developed and widely used for interior decoration.