Acid-alkaline balance is part of the human physiological homeostasis concerning the proper relationship between acids and alkalines, in other words, maintaining a certain pH value within the cellular and extracellular fluids and tissues. Of great importance is that the organism is able to maintain all pH values in the normal range using acid-alkaline buffer systems (blood, lymphoma, kidney, bone and other organs and tissues). Lifestyle and diet negatively affects the balance and often results in a state of chronic metabolic acidosis, which ultimately contributes to the deterioration of many body functions and conditions. Therefore, it is important to bring food supplies that will create an alkaline reaction and so maintain the necessary acid-alkaline balance, and in order to ensure that, it is necessary to consume about 3/4 of alkaline foods. It has been shown that there is more frequent consumption of food that has an acidic effect (cheese, meat, fish, poultry, eggs, refined grains, coffee, beer, wine), and rarer intake of food which is alkaline (fruits except blueberries, cranberries and plums, and vegetables). Therefore, the aim of this study was to examine how much representatives of certain population groups know about which foods in the body are creating an alkaline or acid reaction, and how this affects health. From the results of this study including 38 respondents both sexes age from 19 to 56 we can conclude that younger people (under 24) is slightly more informed about the acid-alkaline foods and the need to maintain acid-alkaline balance of the body. Also, across all age groups women are more familiar with the importance of acid-alkaline foods in the diet than men.