The stability of an efficacious antidote in the treatment of organophosphorous poisoning--HI-6 has been examined in aqueous solutions of eye drops by accelerated stability tests. Disintegration kinetics has been examined at the increased temperatures and pH value of isotonic solution of 25 mg/ml concentration in ampules. First order hydrolysis is larger than in the known oximes: pralidoxime, obidoxime and other due to unfavourable physicochemical properties of HI-6. The period of 44 days which is necessary for reduction of exime concentration in eye drops for 10% at 25 degrees C is not enough for preservation of reliable solution and because of that it should be prepared whenever necessary.