Hexestrol diacetate (brand name Retalon-Lingual among others) is an ester of hexestrol. It is a synthetic estrogen that was used for the treatment of menstruation disorder. It is an estrogen receptor agonist. A single therapeutic dose of hexestrol diacetate administered in impuber sheep has been shown to induce massive follicular atresia. So the incorrect utilisation of some hormonal formulations and the consumption of forages that contain estrogen like compounds, can represent major causes of infertility in sheep.