The present invention demonstrates through many experiments that Rosmarinic acid (RA) can inhibit the expression of connective tissue growth factor (CTGF) and therefore is useful for the prevention or treatment of hepatofibrosis and nephrofibrosis. Based on this, the present invention provides novel uses of RA and pharmaceutical compositions comprising the same in the manufacture of medicaments useful for the prevention or treatment of chronic hepatitis, CRF, and diabetic nephropathy.