The Old Dispensary got its name because it housed a dispensary on the ground floor, along with a pharmacy and doctor. Its building was commissioned by Sir Tharia Topan, who in his heyday had dominated trade in Zanzibar.

The foundation stone of the "Tharia Topan Jubilee Hospital" was put down on 8th July 1885, but Sir Tharia passed away in India in 1891, causing a break in the construction. His widow resumed the works but her finances ran out in 1893 before the building was finished. Yet, the workmanship was brilliant, as acknowledged by Fredrick Pordage, the consulting engineer of the British Consul who saw the building through to completion in early 1894.