Streptococcus is considered to be one of the most dangerous causes of Clinical mastitis in cows. The aim of this study was to investigate the effectiveness of extracts prepared from different parts of the flowing plants: Oleaeuropea Linn(Oleaceae), Myrtuscommunis Linn (Liliaceae) ,thymus vulgaris Linn (Laminaceae), Rosemery Linn(Laminaceae), Ficuscarica Linn (Moraceae), and Achilleafalcata Linn(Asteraceae) against resistant Streptococcus in 1371 Samples of milk. This work was achieved in four stages: First of all, the presence of Streptococcus in 1371 Samples of milk, by using blood agar, Bile Esculin agar, and some bio-chemical tests were investigated .Secondly, the antibacterial activity of many antibiotics on these bacteria by using disc diffusion method were determined.Thirdly, the plants were extracted with water, absolute alcohol, and petroleum Ether by using soxhlet apparatus and rotary vacuum evaporator. Fourthly, the antibacterial activity of the extractions on resistant Streptococcus was determined by using disc diffusion method. This study has shown the presence of different antibacterial effectiveness of the extracts prepared from different parts of those plants. The extract of thymus vulgaris is more effective when compared to the extract of Oleaeur opaea against resistant Streptococcus.