Kryptonite (DC Animated)
From Multiversal Omnipedia
Kryptonite is an element created from the substance of the planet Krypton after its destruction. A radioactive element, it weakens and eventually kills Kryptonians. It also affects natives of Argo, Krypton's sister planet, albeit to a lesser degree.
DC Animated (Comics)
Kryptonite does not affect Argo natives at all.