This is the article on the medicinal drug. For the Konoha Military Police Force captain, head to Kōtarō Fūma.
Kanji 虎打狼
Rōmaji Kotarō
Novel Naruto Jinraiden: The Day the Wolf Howled
Appears in Novel

Kotarō (虎打狼) is a medicinal form of saigenzai that can only be prepared within the bodies of the Kodon clan. It can be prepared with three levels of potency:

  • Refined (上品, Jōhin) - its weakest form but which has zero side effects when taken.
  • Medium (中品, Chūhin) - its middle form which has no side effects if taken in moderation.
  • Coarse (下品, Gehin) - its strongest form but with guaranteed and powerful side effects, with symptoms varying depending on how it is taken.

Itachi Uchiha used the coarse form of Kotarō as an eye drop in order to extend his life, though it caused temporary blindness. Sasuke Uchiha also uses this to eliminate eye irritation as his Mangekyō Sharingan awakens.