Mother's Milk was the name of a genetically engineered poison that was being developed by the Sith Empire in the years of the Cold War. A prototype of the toxin was created by Imodin Ganalya on Alderaan with the express purpose of using it as a bio-weapon against the insectoid Killiks. The poison worked by being injected directly within Killik eggs where they prevented the young from hatching from their eggs thus eliminating them.
The prototype serum was manufactured and the Sith attempted to field test it but their entire field operations team was lost during the mission. Thus, Doctor Ganalya tasked an Imperial official with delivering the poison. Following the successful completion of this task, it was believed the Mother's Milk serum was going to be capable of depopulating an entire Killik nest with thousands of the insectoid aliens failing to hatch from their eggs.
- Star Wars: The Old Republic (First appearance)