Mushi Tobacco (蟲煙草 Mushi Tabako) or Mushi Soot Grass is a plant that either has Mushi repellent properties or is infected with Mushi, and is used to make Mushi cigarettes.
Ginko smokes this Mushi Tobacco in order to repel the Mushi which are endlessly drawn to him. The cigarette smoke is a Mushi itself, clinging to any nearby Mushi, then quickly letting it go. It is completely harmless to both Mushi and humans.
These Mushi do not last for more than a few seconds before dissolving.