The objective of this study was to develop a new Chinese herbal aqua-acupuncture formulation, Dang Hong Fu, and evaluate its efficacy/safety in preventing retained placenta in cows when injected into acupoint GV-1. The safety study in rabbits found no significant adverse reactions. An untreated control group of 124 cows were selected to determine the retained placenta rate for the farm. Fifty pregnant cows from the same farm were selected for the study and randomly assigned to two groups: 30 cows in the Dang Hong Fu group and 22 cows in a saline control group. Immediately after calving 40 ml of Dang Hong Fu (40 grams herbs) were injected into GV-1 in the herbal group and 40 ml of physiological saline injected at the same site in the control group. Both groups were observed for retained placentas and time until placental expulsion was recorded in the others. The retained placenta rate for untreated cows was 35.5%. The incidence of retained placenta in the Dang Hong Fu group was 16.7% and in the saline control group 31%. The time for expulsion of placental membranes had a mean of 9 hours in the Dang Hong Fu group and a mean of 14.7 hours in the saline control group. When compared to the untreated control group, Dang Hong Fu aqua-acupuncture significantly reduced the incidence of retained placentas (p-value = 0.047). Herbal aqua-acupuncture may offer an easy treatment method to reduce the incidence of retained placenta with no adverse side effects.