Compositions for preventing urinary system infections, contain constituents provided for exerting simultaneous actions in order to suppress pathogenic germs causing these infections or to reduce their harmfulness and to reinforce the integrity of the wall of urinary paths. The first action is obtained by constituents which exert an antibacterial action onto germs present in the urinary paths, an antibacterial action onto germs present in the gastro-intestinal tract thereby reducing the colonization by these urinary path germs, and reduce their ability to adhere to the wall of the urinary system. The constituents exerting the first action are polyphenols extracted from garlic and from plants selected from: Ericaceae, Saxifragaceae, Vitaceae and Caprifoliaceae families. The second action is obtained by polyunsaturated fatty acids of the family n-3 that enable the reduction of wall inflammation and the bringing of the immune system back into balance.