Pyometra refers to a life threatening infection of the uterus. All intact female dogs and cats that have not been spayed are at risk. Symptoms of pyometra develop several weeks following a heat cycle that did not result in pregnancy. Pets with pyometra may present for an increase in thirst and urination, lethargy, vomiting, fever, and a foul smelling vaginal discharge. Every sick intact female should be suspected of having pyometra; lack of a vaginal discharge does not rule out pyometra. Diagnosis of pyometra is based on history (usually 2 -3 months after a heat cycle), physical examination, and imaging studies (x-rays and/or ultrasound). Treatment for pyometra requires aggressive fluid therapy, antibiotics, and careful surgical removal of the infected uterus. The best treatment for pyometra is prevention through early spaying, before the first heat cycle occurs.