Blue kryptonite is the Bizarro analogue to green kryptonite. Using Bizarro logic, this, in general, hurts Bizarros while having beneficial effects on ordinary Kryptonians.
Pre-Crisis, blue kryptonite is the result of using Professor Potter's "duplicator ray" on some green kryptonite. Here, blue kryptonite affects Bizarros like green kryptonite affects Kryptonians. Blue kryptonite radiation is not blocked by normal lead, but by imperfectly duplicated lead. Bizarro World had animated Blue Kryptonite golems underground that surfaced and attacked the Super-Powered Bizarros while the delighted non-powered Bizarros cheered them on[volume & issue needed]. In the Super Friends episode "Terror from the Phantom Zone", blue kryptonite heals Superman from the effects of red kryptonite. Post-Crisis, its origin is unknown. Here, blue kryptonite makes Bizarros become polite, goodhearted, coherent, and intelligent.[21] Also, while It does cause physical pain much like green kryptonite affects Superman to Bizarros, its psychological effect is the one thats most disconcerting to them, just like if Superman became illogical, unintelligent and, subsequently dangerous in reverse, but knew the condition wasn't normal, he'd want to return to normal. Normalcy is considered personally and socially undesirable and unbearable to Bizarros, hence their aversion to Blue Kryptonite
In the television series Smallville, blue kryptonite suppresses Kryptonians' powers and removes their sensitivity to green kryptonite. Blue kryptonite was first introduced as a Victory Ring given to Clark by a replicant of his mother Lara-El in "Blue". Also in Smallville, Bizarro's powers were increased exponentially by blue kryptonite- this version of Bizarro being an 'inverted' Clark, weakened by sunlight and strengthened by green kryptonite-, overloading his body with power and killing him, much like "a light bulb being powered by a nuclear reactor", in the episode "Persona".
In episode 7 of season 9, titled "Kandor" Jor-El is shown using blue kryptonite to remove the powers bestowed by Earth's yellow sun upon the Kandorian soldiers led by Zod as he prepares an orb which will carry to Earth the DNA clones of several of the Kryptonian capital's finest soldiers.
In Justice League: Crisis on Two Earths, blue kryptonite has the same weakening effect on Ultraman that green Kryptonite has on Superman.