There has been speculation for decades regarding the role of flushing women's fallopian tubes in improving the chance of pregnancy. More recent evidence has highlighted a possible specific role for lipiodol (ethiodized oil), an oil-soluble contrast medium, in the enhancement of fertility by these means. This systematic review was designed to assess the effectiveness of tubal flushing with various contrast media in improving the chance of pregnancy. The review was performed using Cochrane guidelines, including only data from randomized controlled trials. Results confirm the effectiveness of flushing with lipiodol in improving the chance of pregnancy and live birth. Although there was limited evidence to suggest a possible benefit of oil- over water-soluble contrast media, the answer to this question remains unclear. The specific groups who appear to benefit most from lipiodol flushing are couples with unexplained infertility, but particularly couples where the woman has endometriosis in the context of normal patent fallopian tubes. As a simple, low-cost, minimally invasive intervention that carries a low risk of complications and no increased risk of multiple pregnancy, lipiodol flushing may prove an appealing alternative to established fertility treatments for many couples.