Scientific investigations confirmed that fruits and cladodes of cacti may be efficiently used as a source of nutrients and phytochemicals such as sugars, mucilage, fibres, vitamins and pigments of nutritional and functional importance. Recent data revealed that cactus products show promising characteristics in terms of functionality due to their healthpromoting properties. A detailed description of the major active components of the different cactus species worldwide studied is presented. Since ancient times, cactus plants have been used to cure diseases and to heal wounds. Cacti have been traditionally used as natural medicines in several countries for the treatment of many diseases. Moreover, cladodes and cactus pear fruits are still used in folk medicine as therapeutic agents. Remarkable progress has been made over the past decades in characterizing plant constituents and explaining the role of natural molecules in relation to disease prevention. Cacti can be considered as an important source of bioactive substances and excellent candidates for nutraceutical and functional food preparation. Scientific data revealed high contents of some chemical constituents in fruits, cladodes, seeds and flowers, which can add value to cactus products. Additionally, some of their constituents show promising characteristics in terms of functionality as health promoting substances. Nowadays, the scientific literature concerning the medicinal properties of cactus is in constant expansion, reporting new discoveries about the plant constituents responsible of such activities.