Technical Abstract: Natural toxins from plants and fungi, in addition to man-made toxicants, have been implicated with abortion, embryonic death, or neonatal loss in livestock. Plants causing reproductive problems for livestock can be found on most, if not all rangelands worldwide, thus exposing livestock at various times and circumstances. The impacts of toxins from poisonous range plants on the embryo, fetus, and neonate are sometimes dramatic, and the consequences are economically important to the livestock industry. Historically, reproductive problems due to toxic plants often went undiagnosed and/or unreported because of fears about underlying genetic defects, the related negative impacts on the sale of breeding stock, or because the death of offspring was not associated with any visible malformation such as cleft palate or heart anomalies. However, as more information has been developed about plants affecting reproduction, such fears have largely subsided, and producers are more open to understanding the root causes of the problems. Grazing management strategies using results of research and application of some basic concepts of toxicology have reduced losses to livestock producers. In this review, several plants known to cause abortions in livestock will be discussed with an emphasis on pine needle-induced abortions.