A complex includes RNA and a positively charged modified polysaccharide selected from starch, amylose, amylopectin, galactan, chitosan, or dextrin. The complex can be formed into a pharmaceutical composition. The complex can be used in methods for RNA transfection, gene therapy and treatment of a disease, disorder or condition. The positively charged modified polysaccharide can be used in connection with RNA transfection into cells.