The increasing demand for animals from organic breeding systems has increased interest in certain natural substances, called nutraceuticals, to stimulate the organic defenses of the animals. The aim of this trial was to study the effects of dietary rosemary extract in 36 ewes, from 57 to 154 days of lactation, divided into three groups: CTR (basal diet), ROXLD (600 mg extract/head/day) and ROXHD (1,200 mg extract/head/day). A significantly higher quantity of milk and quantitative daily production of protein, casein, fat, and lactose were observed in the milk of animals in the ROXHD group compared with milk from animals in the CTR and ROXLD groups. No significant differences were observed for somatic cell counts, considering that treated groups showed lower values compared with controls. A significant decrease in clotting time (r) and increase in curd firmness (a ( 30 )) were observed in milk of both treated groups (ROXLD and ROXHD) compared with the CTR group. These results could be related to the significantly higher acidity values, pH and SH degrees , observed in the milk of animals from the treated groups. Dietary rosemary extract in dairy sheep enhanced milk yield, quality, and renneting properties due to its "natural, functional ingredients."