"A small bottle containing tissue samples from Eveline."
— Inventory description for Eveline Tissue Samples.
"A strange bottle that you found in your pocket after waking up at the Baker estate. It's probably important."
— Inventory description for Strange Bottle.
— Item Examination for Strange Bottle.
Eveline Tissue Samples (エヴリンの体組織 Evurin no taisoshiki ) or Strange Bottle (謎の小瓶 nazo no kobin ) is a key item in Resident Evil 7: Biohazard. The Eveline Tissue Samples can't be stored in the Item Box at any given moment. It essentially takes 1 inventory slot from players from the moment is comes to any character's possession.
Eveline Tissue Samples is meant to be used on the medical box in the Storage Space room in the Salt Mine. It will create the E-Necrotoxin for the player to pick up.
As the Strange Bottle, it starts as part of Mia's inventory. After using the Old Videotape section, it is immediately given to Mia in the Guest Room on Ship 2F.
After the player regains control of Ethan on Wrecked Ship S2, it will immediately be given to them or the after the fight with Mia depending on who the player chose to save earlier.