"A special serum for disposing of E-Series test subjects. It could destroy Eveline if injected into her."
E-Necrotoxin (E-ネクロトキシン E - nekurotokishin ) is an item in Resident Evil 7: Biohazard. It can not be removed from the player's inventory once picked up.
Picking up the E-Necrotoxin unlocks the door further into the salt mines. It will be used automatically when approaching Eveline in the Guest House.
E-Necrotoxin is created and made available to pick up after using Eveline Tissue Samples on the case in the lab in the Storage Space room in the Salt Mine.