Isoquercetin, isoquercitrin or isotrifoliin[1] is a flavonoid, a type of chemical compound.

Isoquercitrin can be isolated from various plant species including Mangifera indica (mango)[2] and Rheum nobile (the Noble rhubarb).

It is also present in the leaves of Annona squamosa, Camellia sinensis (tea).

[7] There is a single case report of its use in the successful treatment of prurigo nodularis, a difficult to treat pruritic eruption of the skin.

[8] However it belongs to the PAINS (Pan-assay interference compounds) categories of chemicals.