The research was carried out between October 2007 - May 2008 on an number of 30 12 month old lambs with the porpoise of determining the way in which hydro-alcoholic extracts (50%) of Artemisia vulgaris (mugwort or common wormwood) Ocimum basilicum (basil) and Tymus vulgaris (thyme) influence the hematological parameters, indicators of health, showed fluctuation between physiological limits for most of the investigated parameters. The hematocrit was situated in all groups between physiological limits of 27-45%; the plant extracts not influencing these values. The quantity of hemoglobin in the treated groups with common wormwood and basil extracts varied between 11.09±0.94 and 11.79±0.47 g/dl; administering the thyme extract lead to a “statistically significant” increase (p=0.0111) of hemoglobin from 10.13±1.05 g/dl (det. 1) to 12.05±1.04 g/dl. The most important increase in the level of erythrocytes was noticed in the group treated with the hydro-alcoholic extract of common wormwood, in this case from an average level of 9.73±0.94 (det1) was noticed a “statistically significant” increase (p≤ 0.05) to 11.33±1.14 9det2)and 14.08±4.16(det3). The average erythrocyte constants were characterized by a drop of the average level of VEM in all groups; HEM, regardless of the experiment moment had values situated between physiological limits that fluctuated between 9.73± 1.04 pg and 11.75±1.78 pg; the average level of CHEM was situated above the physiological limits and fluctuated between 34.34±4.98 g/dl (group treated with albendazole), 37.43±2.78 g/dl (group treated with common wormwood), 37.22±2.78 g/dl (group treated with thyme) and 39.20±4.03g/dl (group treated with basil). From the point o view of the leucogram we underline that the number of total leucocytes was situate, during the study in all groups, between physiological limits for the species (4-12 G/l). Before treatment, in all groups the eosinophils were above the physiological limits, the values being of 14.00±5.18% (group 1) 13,20±6,46% (group 2), 17,50±8,14 (group 3), 11,50±7,56% (group 4), 10,83±6,94% (group 5); in case of the group treated with thyme a drop in the eosinophils from 17,50±8,14% (det. 1) to 10,83±7,91% (det. 2) and 10,00±5,80%( det. 3) at the end of the study.