Aim. The objective of the present research was to study the influence of tap water enriched with silver nanoparticles (NP) as well as that of «Krasnoarmeysky» and «Essentuki №17» mineral waters after their single administration through the oral gavage to the rats on the metabolism of carbohydrates and lipids, the biochemical markers of the liver condition, and the endocrine profile in the healthy animals. Material and methods. The laboratory animals (130 male Wistar rats) were allocated to thirteen groups comprised of 10 rats each as follows: 1st group (n=10) intact animals, 2nd group (5 minutes after the administration of silver NP (n=10), 3rd group (15 minutes after the of silver NP), 4th group (60 minutes after the administration of silver NP), 5th group (n=10) (5 minutes after the introduction of the «Krasnoarmeysky» mineral water), 6th group (n=10) (15 min after the introduction of the «Krasnoarmeysky» mineral water), 7th group (n=10), (60 minutes after the introduction of the «Krasnoarmeysky» mineral water) 8th group (n=10) (5 minutes after the introduction of the «Essentuki № 17» mineral water), 9th group (n=10) (15 min after the introduction of the «Essentuki № 7» mineral water) , 10th group (n=10) (60 minutes after the introduction of the «Essentuki №17» mineral water), 11th group (n=10) (5 minutes after administration of tap water (control),12th group (n=10) (15 minutes after administration of tap water (control), and 13th (n=10) group 60 minutes after administration of tap water (control). Results. The study has demonstrated that the tap water enriched with silver nanoparticles similar to the mineral waters caused stress reactions that are inferior to those induced by «Essentuki №17» mineral water in terms of the magnitude; however, the effect provoked by the tap water was of longer duration. Moreover, the tap water enriched with silver nanoparticles stimulates prooxidant reactions, and inhibit the activity of antioxidant protection. Silver nanoparticles appear to produce some destructive effect on the hepatocytes. Conclusions. The silver nanoparticles present in the tap water have a significant biological potential of their own. Moreover, their one-time action is apt to alter the biological potential of the water into which they are administered. The single intake of the tap water enriched with silver nanoparticles by the healthy laboratory animals produces the response that resembles that of the drinking mineral water.