SummaryThe chemical stability of acyclovir sodium in dextrose 5% w/v and sodium chloride 0·9% w/v injections has been studied using a stability‐indicating high‐pressure liquid chromatographic (HPLC) method. The drug appears to be very stable in both admixtures. There was no decomposition after 37 days of storage at 25°C or 5°C. The manufacturer‐recommended expiry date of 24 h at 25°C is too conservative. The solutions were clear throughout the study period and the pH values had decreased slightly in both the solutions. Acyclovir appears to be very stable on the alkaline side of the pH range and less so on the acidic side. There was no loss in the potency of acyclovir when mixed with dobutamine and