Star Wars - A New Threat Arises
Kolto was a liquid that could only be found naturally on depths of the oceanic planet Manaan, and it was known for its healing capabilities. Both the Sith and the Jedi had an equally limited supply of kolto during the Jedi Civil War, and so they sought a way to get more of it to gain an advantage, but all attempts to synthesize kolto failed. In turn, it became a vital export for the economy of Manaan and for the Selkath species that controlled the planet
With the onset of the Galactic Civil War, bacta had become the primary healing agent used in medicine. Aware of kolto’s presence on Manaan and historical significance, Emperor Palpatine invaded Manaan and enslaved the native Selkath.
The Galactic Empire exploited the Selkath and possibly their kolto resources. While kolto was still being used during the Galactic Civil War, it did not possess great value. It appeared to be less effective than bacta, but was used as a cheaper alternative. In their research, however, some historians noted that kolto may have been more effective in the past. By 1 ABY, kolto was in use aboard the Imperial prison barge Purge, where it was administered to some medical patients.
Kolto was also one of the primary components of medpacs during the Jedi Civil War. Medpacs contained small amounts of the liquid for easy carriage and transport. Therefore, the amount of kolto was usually not substantial, so medpacs functioned primarily as first aid supplements.