In February 1855 Williams, now a lieutenant-general in the Turkish army, appointed Sandwith inspector-general of hospitals, placing him at the head of the medical staff. Meanwhile, Colonel Henry Atwell Lake was fortifying Kars, and in the beginning of June, when the siege was imminent, Williams and his staff took up their quarters there. During the Siege of Kars, which lasted till the end of November, Sandwith had to contend with cholera and starvation; and after the assault of 29 September he had wounded men, both Turkish and Russian, on his hands. He had to rely mainly on horseflesh broth for his patients.