You are probably here because another site told you GRAIN ROT has a Rot Sickness stat that fills up and needs curing. Before you go looking for it in game: nobody has shown that it exists.
What the developers actually say
“The Deep Layers are filled with Corrupted vessels, reacting to sound, movement, and each other.”
And on going deeper: “Bodies warp. Voices distort. Emotes become…worse.”
That is the whole official record on the subject. It describes a progressive effect on your vessel as you descend — which is clearly something, and is clearly the thing the phrase “Rot Sickness” is reaching for. What it does not describe is a named status, a meter, a percentage, a threshold or a cure.
Where the phrase came from
Community “Rot Sickness” is search vocabulary. Players needed a handle for “the thing that happens the deeper you go”, the phrase stuck, and guide sites then wrote pages describing it as though it were a documented system — complete with percentages and a meter that appears in no official material at all.
We are not going to reprint those numbers. If we cannot point at where a figure came from, publishing it just moves the invention one site further along.
The two real things underneath it
1. The deep layers change your vessel
Officially confirmed, quoted above. Bodies warp, voices distort, emotes degrade. This is atmosphere with teeth — it tells you how deep you are without a UI element.
Community Players describe it as progressive rather than a switch, and tie it to depth rather than to time spent. We have not found a source precise enough to tell you where any thresholds are, and we are not going to guess at them.
2. Grain Rot is a physical growth you burn
This one is concrete, and it is a completely different mechanic from anything happening to your body.
“Fixed a bug where Grain Rot was visible through certain unrepaired ceiling modules.”
The growth is tracked per module, which is a strong hint that it is an object in the world rather than a status on you. Players clear it with fire when the Outpost’s second floor opens — the full method is on the floor 2 page, including which fire sources work and the warning about lanterns spilling flames if you smash them lit.
So what should you actually do?
Nothing, as far as any “sickness” goes. Go as deep as your nerve allows, watch your vessel start to look wrong, and take that as the atmosphere doing its job.
The things that genuinely end runs are noise, greed and stamina — covered on the beginner guide — and losing your vessel is cheap anyway, because the Spark survives it.
If we are wrong
If GRAIN ROT does have a rot meter with numbers on it and you can show us, this page changes the same day. That is a far more useful outcome than us inventing one to match what everybody else published.