Estus Flask

Estus Flasks are a consumable item in Dark Souls, allowing the Undead to replenish missing health. The Estus Flask is one of the most iconic items in the series, symbolizing the cycle of life, death, and rebirth central to the game’s themes.

The Undead treasure these dull green flasks.
Fill with Estus at Bonfire. Fills HP.
The Estus Flasks are linked to the Fire Keepers. The Dark Tales also make reference:
An emerald flask, from the Keeper's soul. She lives to protect the flame, and dies to protect it further.

Usage

Estus Flasks can be consumed by placing them either in the player's quick access (highly recommended) or navigating to the flask in the inventory. They have a limited number of uses, indicated by an overlaid number, and can be replenished by resting at a bonfire. The number of Flasks returned when resting at a bonfire depends on its level of kindling, starting at 5 flasks, then increasing to 10 when the bonfire has been kindled and 15/20 once the player has acquired the Rite of Kindling and can kindle the bonfire further. It costs the player 1 Humanity point to kindle a bonfire.

Additionally, drinking an Estus Flask will heal summoned players in co-op, but not NPC co-operators. 

Acquisition

Granted to the player at the start of the game as an item found on the corpse of Oscar of Astora. If not picked up in NG+, can be found in the chest behind Frampt in Firelink.

Upgrades

Can be upgraded with a Fire Keeper Soul up to +7 in order to restore more HP per sip. A Fire Keeper Soul must be given to one of the three Fire Keepers, Anastacia, The Fair Lady, or the Darkmoon Knightess.

Notes

• Killing a Fire Keeper (e.g., Anastacia) disables the ability to reinforce Estus Flasks until their soul is restored.
• If you rest at a bonfire that has been kindled by another player in the same network, you may receive one bonus charge as part of the multiplayer connectivity feature.
• The Estus Flask is tied to the bonfire system, representing the player’s connection to the Fire Keepers and the dwindling flames of the world.
• Estus Flask charges do not carry over to New Game Plus, requiring players to re-kindle bonfires. However, reinforcement levels (e.g., +7) are retained.

Trivia

• The word “Estus” derives from the Latin word aestus, meaning "heat" or "fire," symbolizing its connection to the First Flame and the bonfire system.
• The Estus Flask was inspired by the "healing gourd" mechanic from Demon's Souls, which had a similar function but required farming for consumables.
• The golden glow of the flask reflects the essence of fire, contrasting with the dark blue or purple hues of Humanity-based items.
• In Dark Souls II, the Estus Flask takes on a different origin, linked to the Emerald Herald and the game's fragmented connection to the First Flame.
• According to lore, the Estus Flask contains the essence of bonfire flames, imbued into a physical vessel to serve as a portable source of healing.
• During early development, the Estus Flask was considered a finite resource, but the refillable system was introduced to encourage exploration and reduce farming.
• The animation for drinking from the flask leaves the player vulnerable, emphasizing the importance of timing and strategy in using it.