The effects of ethanol, tweens and antioxidants to sodium ampicillin solution are studied. From the result of this experiment, 10% sodium ampicillin solution degradation decreased with addition of 1.0% Tween 80 or Tween 60. The sodium ampicillin solution added antioxidants such as 0.2% rongalite, 0.2% Na$_{2}$S$_{2}$O$_{4}$, 0.2% Na$_{2}$S$_{2}$O$_{5}$ 0.2% NaJ degraded more rapidly than the solution.n.