The literature on the identification, assay, and use of metronidazole has been surveyed. Based on published information, private communications, and laboratory experimentation, qualitative tests and quantitative assays have been developed for metronidazole, metronidazole suppositories (vaginal tablets), and metronidazole tablets. Extraction of metronidazole from suppositories and tablets is with hot acetone. Assays are based on titration of metronidazole in acetic anhydride with 0.1 N perchloric acid in glacial acetic acid, using malachite green indicator. The visual endpoint coincides with that determined potentiometrically. Supporting data is presented, including UV and IR spectra.