Background: Lymphatic pump treatment (LPT) is a technique used by osteopathic physicians as an adjunct to antibiotics for patients with respiratory tract infections, and previous studies have demonstrated that LPT reduces bacterial load in the lungs of rats with pneumonia. Currently, it is unknown whether LPT affects drug efficacy. Objective: To determine whether the combination of antibiotics and LPT would reduce bacterial load in the lungs of rats with acute pneumonia. Methods: Rats were infected intranasally with 5x107 colony-forming units (CFU) of Streptococcus pneumoniae. At 24, 48, and 72 hours after infection, the rats received no therapy (control), 4 minutes of sham therapy, or 4 minutes of LPT, followed by subcutaneous injection of 40 mg/kg of levofloxacin or sterile phosphate-buffered saline. At 48, 72, and 96 hours after infection, the spleens and lungs were collected, and S pneumoniae CFU were enumerated. Blood was analyzed for a complete blood cell count and leukocyte differential count. Results: At 48 and 72 hours after infection, no statistically significant differences in pulmonary CFU were found between control, sham therapy, or LPT when phosphate-buffered saline was administered; however, the reduction in CFU was statistically significant in all rats given levofloxacin. The combination of sham therapy and levofloxacin decreased bacterial load at 72 and 96 hours after infection, and LPT and levofloxacin significantly reduced CFU compared with sham therapy and levofloxacin at both time points (P<.05). Colony-forming units were not detected in the spleens at any time. No statistically significant differences in hematologic findings between any treatment groups were found at any time point measured. Conclusion: The results suggest that 3 applications of LPT induces an additional protective mechanism when combined with levofloxacin and support its use as an adjunctive therapy for the management of pneumonia; however, the mechanism responsible for this protection is unclear.