Diabetic foot ulcers (DFUs) are highly vulnerable to infection and pose risk for limb amputations. Studies have shown that ozone therapy reduces wound size and improves wound healing time better than standard treatments. We examined the effectiveness of combining standard wound care with ozone therapy to reduce bacterial colonization and accelerate healing of DFUs in the home care setting. The control group (n = 12) received standard wound care with antimicrobial dressings every 3 days for 21 days, and the intervention group (n = 15) received the same as control group plus ozone bagging therapy at 70 μg/mL for 10 minutes every 3 days for 21 days. Combining standard wound care with ozone therapy significantly decreased the number of bacterial colonies (p = 0.001). However, no significant difference in DFU assessment score was found between the intervention and control groups (p > 0.05). Combining standard wound care with ozone therapy reduced the number of bacteria in the DFUs but exerted no significant effect on wound healing. Future studies should examine the administration of ozone therapy with different concentrations and times of exposure to explore the right dose for healing DFUs.