Should I upgrade Noxious Fumes in Slay the Spire 2?

Compare the upgraded text: At the start of your turn, apply 3 Poison to ALL enemies.. If the upgrade lowers cost, adds damage/block, or enables a combo piece, it is usually high priority.

What builds use Noxious Fumes?

Noxious Fumes appears in 1 tracked build: Venom Cascade (S-tier, hero card).

What character uses Noxious Fumes?

Noxious Fumes is tagged as a Silent card. See the Silent build hub for archetypes that care about it.

Updated for Data 2026-03-17Early Access — numbers may shift with patches.

Noxious Fumes

Silent · Power · Uncommon · 1 cost

Base

Upgraded

Card text

At the start of your turn, apply 2 Poison to ALL enemies.

Noxious Fumes+

At the start of your turn, apply 3 Poison to ALL enemies.

Builds that use Noxious Fumes

Archetypes that draft this card in real runs, with the role it plays.

SVenom CascadeSilent · Hero card

Keywords

Poison

Build context

See the Silent build hub for archetypes that feature this card in real runs.

Related cards

Noxious Fumes FAQ

Should I upgrade Noxious Fumes in Slay the Spire 2?: Compare the upgraded text: At the start of your turn, apply 3 Poison to ALL enemies.. If the upgrade lowers cost, adds damage/block, or enables a combo piece, it is usually high priority.
What builds use Noxious Fumes?: Noxious Fumes appears in 1 tracked build: Venom Cascade (S-tier, hero card).
What character uses Noxious Fumes?: Noxious Fumes is tagged as a Silent card. See the Silent build hub for archetypes that care about it.

Patch history

SpireForge snapshots card text from Untapped exports dated 2026-03-17. When Mega Crit ships a balance patch, we re-run the scraper and refresh every affected URL—see /patches for the editorial log.