Of 12 cows with post-partum purulent endometritis 6 were treated intramusculaly with 25mg of prostaglandin F2α (PGF2α) in 5ml saline and the remaining 6 received 5ml saline. They were examined for cervical mucus and histopathology of the biopsyed endometrium. All the PGF2α-treated animals showed estrous signs 4 days posttreatment (pt). In most of them, neutrophils in the cervical mucus and macrophages in the endometrium disappeared or significantly decreased on 14 days pt. Lymphoid accumulation in the endometrium was less remarkable than the control group. The control group showed neither the estrous sign nor improved findings in the cervical mucus and endometrium during 14 days pt.