Kolto was a medical substance in use during the time of the High Republic Era. During a skirmish on the Amaxine space station against Nihil marauders, the Jedi Wayseeker Orla Jareni shut emergency doors to prevent the Nihil from reaching her and fellow Jedi Cohmac Vitus. Vitus began coughing, having inhaled dust particulates as a result of the long-dormant doors closing, but stated that the issue would be easily fixed by a kolto rinse.

Kolto was first canonically mentioned in the 2021 young adult novel The High Republic: Into the Dark, written by Claudia Gray. In the Legends continuity, kolto originated in the video game Star Wars: Knights of the Old Republic.

Bacta was a thick, gelatinous substance with seemingly magical healing properties. It helped the body regrow tissue, including nerves, skin, and muscles.

Bacta was a mixture of kavam and alazhi bacteria combined with ambori fluid and a type of barley known as Vratixia renanicus.

Promoting rapid regeneration of organic compounds, bacta could be used in a variety of both critical and noncritical medical situations. Described as being warm to the touch, the bacta liquid could aid in the healing of concussions, internal organs, and broken ribs. Furthermore, it could be placed in small dishes to help regrow fingernails, mend cuts, burns, and other injuries. Due to its «one-size fits all» use in medical applications, it was a highly prized and commonly used medical treatment for most, if not all, injuries. Bacta could also knit together broken bones.

Despite its highly regenerative properties, some individuals harbored negative feelings towards the substance, finding its viscosity somewhere between liquid and slime. Additionally, most bacta patients felt as if they were being swallowed alive upon being submerged in the substance. As such, most doctors injected sedatives first, while subsequent waves of relaxation would slowly overcome the patient, sending them into a meditative state. While most retained consciousness, the combination of drugs and bacta commonly lead patients to feeling like they were drifting into another world, with some comparing it to being in a mother’s womb. Upon emerging from the liquid, many would describe feeling worse for a few days due to the loss of serenity precipitated by the substance. However, some would find the opposite to be true, describing their bodies as feeling light and free from pain.

In order to allow a patient to retain normal functions, a breathing apparatus was provided to the individual along with specialized sensors that allowed the doctor to monitor their patients’ bodily functions while submerged.