Bacteriostatic Water is water for injection that has an expiration date exceeding one year. This product is a preparation designed solely for parenteral use only after addition of medication that require dilution or repeated withdrawals may be made to dilute or dissolve medication for injection, Water for injection is chemically designated H2O which contains 0.9% (9 mg/mL) of Benzyl Alcohol added as a bacteriostatic preservative with a shelf-life of 18 months.