Pelvic inflammatory disease (PID) typically results from ascending infection through the endocervix, from the lower to the upper genital tract. This leads to inflammation of the endometrium, uterus, fallopian tubes, adnexal structures or pelvic peritoneum. It is extremely common and accounts for one in 60 GP consultations by women under the age of 45 years. PID may cause significant short- and long-term morbidity. Whereas most patients are asymptomatic, others may present acutely unwell with pelvic peritonitis and septicaemia. The long-term effects of PID include chronic pelvic pain, subfertility and ectopic pregnancy. However, there may also be substantial psychological morbidity in the form of guilt, isolation, and stigma associated with the diagnosis.  Although PID may occur following pelvic surgery, after instrumentation of the uterus and even in the puerperium, the most common cause is sexually transmitted infection (STI).