Thaumatococcus is a monotypic genus of tropical flowering plant, containing the single species Thaumatococcus danielli, known for being the natural source of thaumatin, an intensely sweet protein which is of interest in the development of sweeteners. It is a large, rhizomatous, flowering herb native to the rainforests of Ghana and surrounding African nations. It is also an introduced species in the rainforests of northern Australia. It grows three to four meters in height, and has large, papery leaves up to 46 centimeters long. It bears pale purple flowers and a soft fruit containing a few shiny black seeds. The fruit is covered in a fleshy red aril, which is the part that contains thaumatin. In its native range, the plant has a number of uses besides flavoring. The sturdy leaf petioles are used as tools and building materials, the leaves are used to wrap food, and the leaves and seeds have a number of traditional medicinal uses.
Common names for this species include miracle fruit (but the unrelated species Synsepalum dulcificum is better known by that name) and miracle berry; also katamfe or katempfe, Yoruba soft cane, and African serendipity berry.
A gene from Thaumatococcus daniellii has been inserted into a cucumber plant to increase its perceived sweetness in human eaters by the Warsaw University of Life Sciences.