The objective of this study was to estimate the influence of per os N-acetylcysteine (NAC) administration on total somatic cell count (SCC) and their composition in goat milk depending on the presence of pathogenic bacteria. The study was conducted on 12 Polish White Improved (PWI) dairy goats, 3-7 years old, between 150^th and 180^th day of lactation. The milk samples (total 68) were taken from separate udder halves, three times during the study: just before NAC supplementation and on 8^th and 15^th day of the experiment. The total SCC and their composition was determined using flow cytometry. The milk samples were also cultured for presence of pathogenic bacteria which were revealed in the half of them. N-acetylcysteine administration influenced the total SCC, the content of total leukocytes and particular leukocyte subpopulation in total SCC both in milk from healthy and infected haves of an udder.