A study was carried out in 12 healthy volunteers to assess the bioavailability of two different oral formulations of amoxicillin (CAS 26787-78-0). A single 1000 mg oral dose of drug was given according to a randomized two-way crossover design as tablet (treatment A) and capsule (treatment B, Gramidil) and blood samples were drawn at selected times during 24 h. A 7-day wash-out period separated each dose. Amoxicillin plasma concentrations were determined by HPLC, and the stability of drug was studied to verify the possibility of an automated batch processing overnight. Amoxicillin was rapidly absorbed after administration of either formulation and individual plasma concentration-time profiles were constructed. Cmax and AUC values were compare by analysis of variance (ANOVA) followed by Westlake's confidence interval test. 95% confidence limits ranged from 80 to 125% for Cmax and AUC. With respect to tmax, Friedman test was used to compare formulations. It is concluded that the two assayed amoxicillin formulations may be considered to have the same bioavailability.