The Vietnam conflict, which lasted for two decades in the mid-twentieth century, was one of the largest confrontations of the Cold War era between the two antagonistic poles of the world community, most notably the United States and the USSR, as well as their satellite countries. The Vietnam War also became a huge testing ground, in which the leading powers not only defended the values of their world views, but also widely used the latest weapons in real conflict. In addition to the comprehensive direct confrontation of the forces of the enemy on the ground, this conflict is also remembered for the large-scale use of the technical innovations of the era, primarily in the means of war in the air and the means of air defense. One type of aircraft used throughout the conflict was the C-123 Provider transport, developed by the Chase Stroukoff Aviation Co in 1949, which was later swallowed up by Fairchild, another well-known corporation. This aircraft was extensively operated in the sky of Vietnam, delivering soldiers and equipment to the roughest areas of the East Asian country. Unlike other aircraft of this class, it had very good takeoff and landing characteristics, which allowed it to land and take off in quite difficult conditions. Initially, these were C-123B machines, which were later upgraded to the C-123K standard by installing additional jet engines under the wing, which improved their landing capabilities even further. In the early 1960s, several C-123Bs were involved in an operation to remove from the air the populations of tropical mosquitoes that carried malaria and other dangerous diseases in the region. For this purpose, special spray tubes were installed under the wings, and the mosquito poison itself was fed to them from the tank inside the aircraft fuselage. About 10 airframes were converted for this task, and they proved effective for the meanwhile. However, this was merely the harbinger of that dark page in the thousands of books about this conflict, in which the future activities of the C-123 would soon be permanently written. In the early 1960s, it finally became clear that the conflict would drag on indefinitely. Ongoing support for North Vietnam by the USSR and China, not only in the form of 'volunteers' but also with military equipment, had left the situation at a complete standstill. Matters were further complicated by the inability to effectively combat the proliferation of military equipment in the jungle, as the thick foliage impeded the effective conduct of aerial reconnaissance and the ability to attack the guerrillas directly from the air. Under these conditions, it was decided to apply heavy duty chemical poison, such as herbicides, to maximize the destruction of vegetation. Already in 1962, a special herbicide-based chemical reagent, called Agent Orange, was tested at a testing ground in the United States. The choice of aircraft for this mission was not difficult - the C-123 was ideally suited to this specific task. A 1,500-gallon tub was installed in the converted cargo compartment and other special equipment operated by an additional crew member. The poison was fed through the piping system not only under the wing as in the previous case, but also to the sprayer behind the fuselage, which increased the density of the spray of the deadly substance per unit area. The new variant was designated the UC-123K, and in addition to special equipment, they also organised new procedures, since the poison spraying had to occur from a minimum height directly above the tree tops. In these circumstances, even shots from conventional small arms could be dangerous to the aircraft, and so training the crew was essential. Twenty-five C-123K aircraft were converted to a similar standard, creating a special aviation unit. In the following years, they would conduct thousands of dangerous missions, dropping countless tonnes of poison over the surface of Vietnam. Named Operation Ranch Hand, this work was subsequently practised by the military with increasing volume. In 1968, the success of the UC-123K's activities was so significant that the military command even gave it priority over other aviation activities during the conflict. In total, about 1,250 pilots and specialists were involved in the operation, and only 5 of the 25 aircraft were lost during missions. The total hits inflicted on the UC-123K from the ground exceeded 7,000, and one of the planes, which had its own name, Patches, received more than 500 of them just by itself, but survived the conflict and is currently on display at one of the US aviation museums. At the end of the operation, about 15 aircraft, which were considered fit for further use, were converted back to the C-123K standard, by removing all special equipment and carrying out complete disinfection. Unfortunately, the Vietnam conflict, like any other war, was not a model of humanity or humanity. The damage from the defoliants that the C-123 sprayed over tens of thousands of acres was very significant, not only for vegetation but also for humans. Numerous diseases and deaths have affected not only Vietnam residents - many members of the C-123 crew have died in the decades since from the effects of direct contact with the toxic poison, most notably carcinogenic diseases. Given the widespread propaganda campaign that the Soviet Union has waged since the 1970s, and the argument for the use of hazardous chemical weapons in the skies of Vietnam, the fact of the involvement of the C-123 being mainly now mentioned as a poison sprayer in historical studies of the conflict does not detract from the important role played by the C-123 as a whole during this prolonged military confrontation.