PROBLEM TO BE SOLVED: To obtain a cell active substance with which, for example, energy metabolism/proliferation activity of fibroblast can be improved, which is effective for prevention of the skin from getting older and amelioration of function, can increase activity of eosinophil leucocyte and is effective for allergies such as atopy, etc. SOLUTION: This cell active substance is a cell active substance which is obtained by carrying out an operation of separation of at least a part of an inorganic salt dissolved in marine water to give (concentrated) desalted marine water and further performing a separation operation at least one time. The cell active substance includes a skin cell activator and/or an immunocyte activator. This medicine and this cosmetic contain the cell active substance.
