- Black Currant is known to be a good source of minerals and vitamins, especially vitamin C. It has cleansing, diuretic, diaphoretic and febrifuge actions, helps to increase bodily resistance to infections and is a valuable supportive for helping support coughs and colds. Black Currant is used along with other supplements to help support symptoms of and help stimulate the immune system. By encouraging the reduction of fluids, Black Currant helps reduce blood volume and thereby support healthy blo