Drugs, nutrients and other solutes are administered to fixed and mobile tissue cells of the mammal in an aqueous solution containing about 75-200 mM/L of Na.sup.+ , about 7-75 mM/L K.sup.+ , about 12-28 mM/L HCO.sub.3 .sup.- , about 70-195 mM/L Cl.sup.- and preferably containing about 3-8 mM/L Mg.sup.+.sup.+ and about 3-8 mM/L HPO.sub.4 .sup.= and/or SO.sub.4 .sup.= , and/or acetate, and/or gluconate.sup.- ; the solution having a pH of about 7.4 to 8.4 and an osmolality of about 170-460, prefera...