 [ Symptoms ] where is the best place to start learning to become a healthy more active individual [ Disease ] if it does it is written on the bottle that is a good question i know that i have used bottles that i have kept around for years mostly on my dogs when the get skunked i think hydrogen peroxide is very stable and can last for a long time in a sealed bottle but if you are ever in doubt just buy a new one it is also very inexpensive