Abstract We investigated the effects of crude ingredients that compose Juzen-taiho-to (Shi-quan-da-bu-tang) and Ryutan-shakan-to (Long-dan-xie-gan-tang) using in vitro and in vivo experimental models. Juzen-taiho-to consists of 10 crude ingredients extracted from herbs: Astragali Radix, Glycyrrhizae Radix, Cinnamomi Cortex, Rehmanniae Radix, Paeoniae Radix, Cnidii Rhizoma, Atractylodis Lanceae Rhizoma, Angelicae Radix, Ginseng Radix, and Hoelen. Ryutan-shakan-to consists of 9 crude ingredients extracted from herbs: Scutellariae Radix, Glycyrrhizae Radix, Gardeniae Fructus, Rehmanniae Radix, Plantaginis Semen, Alismatis Rhizoma, Angelicae Radix, Akebiae Caulis, and Gentianae Scabrae Radix. For the in vitro experiment, the minimum inhibitory concentration of each extract of crude ingredient against Escherichia coli (GOG 0020) was > 100 μg/mL. For the in vivo experiment, 16 hours after inoculating rats with 8.1 × 10 6 colony-forming units of E coli, each extract of crude ingredient (125 mg/kg in 1 mL physiologic saline) orally three times a day or 1 mL physiologic saline alone (control) was administered to rats by gavage orally three times a day for 7 days. The extracts showed no in vitro antimicrobial activity, but extracts of Hoelen, Rehmanniae Radix, Glycyrrhizae Radix, Cinnamomi Cortex, Cnidii Rhizoma, Angelicae Radix, and Alismatis Rhizoma in both regimens significantly decreased the viable E coli counts in rat uterine infections.