Throughout history, epidemics were an important cause of human deaths in addition to natural disasters such as earthquakes, fires, famines, and climate disturbances. The most deadly of these epidemics was the plague. The plague, which caused the deaths of millions of people in three major pandemics or global epidemics, was eliminated in Western Europe in the late 17th century. It continued to surface in the Ottoman area, bridging the east and the west, and caused significant destruction until the first half of the 19th century. The Ottoman territories suffered greatly from plague outbreaks, which emerged in the Far East and journeyed to the west from there. Fortunately, in the Ottoman Empire, the plague lost its former power in the first period of the 19th century because of the quarantine system, which was implemented in the 1830s. However, eventually a more dangerous epidemic disease, cholera, became a global threat in this period. Cholera, which was an endemic disease in India until 1817, subsequently spread rapidly out of the country and was evident in Asia, Africa, Europe, and America. It caused great pandemics within a century. The quarantine system established against the plague epidemics of Europe proved to be inadequate against this new disease. Spreading all over the world, cholera cost thousands of lives until the necessary measures were taken. According to studies on cholera, it has had six major pandemics in the 19th century, namely, in 1817, 1829, 1852, 1863, 1881, 1889, and during 1892–1895. The six major cholera pandemics followed three main routes to reach the west. The first was the route that reached Russia via North India, Afghanistan, Persia, and Central Asia. The second was the sea and highway passing through the Oman Sea and Basra Gulf to Baghdad. The third was the sea route that leads to India through Egypt and Mediterranean via the Red Sea. As Pollitzer stated, the cholera outbreak of 1847–1848 was a part of the second pandemic period of 1829–1851. The disease, which emerged in India, continued to spread towards the West, reached Europe in the 1830s, and killed innumerable people. The disease reached Istanbul for the first time in 1831 and took more than 5,000 lives in the capital. However, it was more devastating in the Hejaz, the western part of modern-day Saudi Arabia. Cholera reappeared in India in 1840, and quickly spread to the West. In its path, cholera brought devastation to Persia. By virtue of the geographical location and breadth of the country, epidemics were very common in Persia. Persia—adjacent to Russia across the Caspian Sea, to the Persian Gulf in the south, to the Ottoman Empire in the west, and to Afghanistan and the British Indies in the east—served as a bridge for disease movement from the east to the west. The outbreak that occurred in 1840 spread to Persia in 1845 and left more than 20 thousand dead. The disease reached the Ottoman territories via Persia and appeared in Erzurum, in eastern Turkey, in late 1846. In the summer of 1847, the evidence of people afflicted by the disease, which had been seen since the beginning of the year in the city, showed a great increase and caused nearly a thousand people to die. Likewise, the disease continued to occur in the surrounding areas as well as in Erzurum. Cholera, which spread from Persia to Georgia, moved across the sea to reach Trabzon in northeastern Turkey in September 1847. Panicked by the plague, the people of Trabzon evacuated town; despite this, approximately 1,200–1,300 people died between September and October, according to the information received from the city’s quarantine authorities. Because of the quarantine regulations, trade came to a halt for three months after the outbreak. However, the Quarantine Council abolished the quarantine regulations for the sea route in late October as the epidemic weakened. Trabzon faced the worst losses in 1847 in the southern Black Sea coast. The epidemic of 1847–1848 primarily affected Istanbul. The first cholera epidemic, which appeared in 1822 in the Ottoman lands, was seen in Istanbul for the first time in 1831. A ship from Odessa transmitted the disease to the capital. In this period, there was no experience of this disease in the capital and the quarantine system was not yet established. It is stated that in the first visit of the disease, it claimed more than 5,000 people of Istanbul were victims of the disease. A similar threat resurfaced in Istanbul 16 years later, at the end of 1847. According to sources, the disease arrived in Istanbul by a steamship from Trabzon. The first case was discovered on September 12 on the steamship Sultan from Trabzon. Because of this, both the Sultan and other ships from direction of Trabzon were subjected to a 10-day quarantine in the Kavak Quarantine Station. At the end of 1846, the news that cholera had appeared among the pilgrims in Mecca spread in İstanbul. Moreover, three people died in the steamship Stamboul, which journeyed from Trabzon to Istanbul. The second case occurred in Ortaköy and the third in Beyoğlu district. In November, the disease continued to proliferate in the capital. In Galata on November 2–4, 7 cholera cases were noted. Later, the disease spread to Tatavla, Beyoğlu, Kasımpaşa, Balat, and İstinye districts and changed to its direction so that it was observed also in Hasköy, Fener, Üsküdar, and finally in the center of Istanbul. By the end of December, cholera was seen in the warships that anchored in the shipyard of Tersane-i Amire. According to the reports of foreign physicians in the capital, the disease, which continued to be infectious in the capital during the first months of 1847, increased its effects in the spring period when the weather warmed. In addition, the epidemic spread to all the districts of Istanbul. Death cases were usually seen in places where adequate hygiene measures were not taken and which were inhabited by mostly poor families. Mortality rates rose in July–August when the weather was warmest. The month of Ramadan, which coincided with this period, increased mortality rates. However, it was announced on October 18 that cholera had entirely lost its influence in Istanbul. During this epidemic period, nearly 10,000 people were affected and, according to different sources, more than 4,000 people succumbed to the disease. With the help of Turkish and foreign physicians, the authorities of the capital assumed a series of measures to fortify public health against the effects of the cholera, which paralyzed life in Istanbul for a year. Although we could not delineate the course of the disease as in the example of Erzurum, Trabzon and Istanbul, the 1847–1848 cholera was also effective in other regions of the empire. For example, more than 500 people in Kars fell victim to the disease, and in Çıldır, Ardahan, Penek, Oltu, Olur, and Narman districts, the outbreak claimed the lives of a thousand people. The epidemic showed its influence in the southeast of Anatolia and advanced through Diyarbakir, Mardin, and Siirt. In addition, cholera caused catastrophic damages in Hejaz and took 15,000 lives. However, the disease, which also appeared in other parts of Anatolia and Rumeli, began to lose its effect in October 1848. In this way, the disease that progressed rapidly not only in the Ottoman territory but also in all the surrounding countries caused many deaths and astonished the scientific world for some time. The European states were required to muster international cooperation to adopt better and more effective measures against cholera outbreaks. In this context, international health cooperation was initiated with the first International Sanitary Conference in Paris, which opened on July 23, 1851. The objective of this conference was to unify and reduce to a safe minimum the conflicting and costly maritime quarantine requirements of different European nations. As a result, we find that new documents and findings in local history research can reveal the effects of epidemic diseases in Ottoman provinces. However, for the early periods of the cholera epidemics, the Ottoman archival sources are not detailed in this regard, but consular reports provide important information on the spread and progress of the diseases. As consuls were primarily trade officials, they particularly focused in their reports of events that can affect commercial relations in their consular regions. Since epidemics such as plague and cholera affected interregional trade, consuls gave detailed information that we could not find in Ottoman documents on the progress of the disease as it is evident in the consular correspondences on Erzurum and Trabzon. Undoubtedly, applying this method to the other provinces in terms of the history of cholera or other epidemic diseases will make new contributions to the subject.