The paper analyses the goals pursued by the Russian Empire through the establishment in 1836 of a Quarantine posts at the entrance into the Sulina branch of the Danube. Our research shows that the establishment of a quarantine post at the entrance into the Sulina branch, instead of the one at the entrance to the Kilia branch, was the result, first of all, of a geopolitical game, which Russia adopted to curb the growing influence of the great European powers in the Lower Danube region. The sanitary challenges, which were undoubtedly substantial in this period, were cleverly used by the tsarist authorities to mask its primordial interests. This fact becomes clear following the changes they carried out in the organization of the sanitary-customs cordon on the Danube, immediately after the signing of the Adrianople Peace Treaty in 1829. Moreover, the inspection of the vessels going up the Danube heading towards Galati and Brăila was superfluous, since even the Russian occupation authorities in the Romanian Principalities (1829-1834) took care to establish quarantines in these ports, and the directing of suspicious vessels to the quarantines in Ismail or Odesa raises even more question marks. Finally, the establishment of the quarantine post at Sulina after leaving the Romanian Principalities amply demonstrates that the interest was to maintain control over them.