OBJECTIVES: The aim of the study was to investigate the effect of a short-term high-salt diet on the formation of reactive oxygen speacies in leukocytes, isolated from the peripheral blood of healthy young women by the use of DCFH-DA fluorescence dye and then measurements of a DCFH-DA in peripheral blood leukocytes by the flow cytometry. STUDY DESIGN: The whole study is a non-randomized controlled clinical trial. All measurements on respondents were made before and after the dietary protocol and they served as a control group. MATERIAL AND METHODS: The study included 15 healthy young women. During the study, all respondents visited the LKFFS three times. In the first week of the study, all respondents ate low-salt food with a maximum salt intake of about 2.3 grams per day. After the first week of LS diet, the respondents were on a week-long HS diet that included salt intake about 14 grams daily. During each visit a sample of venous blood (for flow cytometry) and a 24-hour urine sample (for controlling abidance of the given diet protocol) was taken from all respondents. RESULTS: The study shows that the values of arterial pressure and pulse were not significantly altered before and after the protocol. After HS diet protocol, sodium excretion in 24-hour urine sample was statistically significantly increased. A week on HS diet significantly increased basal production of ROS in peripheral blood monocytes of healthy young women compared to the measurements before the HS diet. PMA stimulation increased ROS production significantly in peripheral blood monocytes before and after the HS diet in healthy young women. CONCLUSION: Food with a high-salt content often lead to an increased production of reactive oxygen species in cells, while blood presure and pulse rates are not significantly altered. However, stimulation with PMA also leads to increased ROS products, either before or after the HS diet.