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Medical Systems & Surgery

By ScotPublished Updated Sources checked

Tactical Quick Answer

Tend quality decides whether a sick pawn beats a disease, and it comes from three things together: medicine potency, the doctor's medical skill, and room cleanliness. Surgery follows the same logic, so build a sterile, well-lit hospital with high-quality medical beds and save glitterworld medicine for critical operations. Bionics boost stats but run into hard global caps, so a brain-damaged pawn will never reach superhuman manipulation no matter how many bionic arms you install.

RimWorld's medical system dictates the line between life and death. Understanding how tending, diseases, and surgeries work is critical. A bad doctor in a dirty room is worse than no doctor at all.

Tend Quality and Diseases​

When a pawn catches a disease or suffers an injury, they need to be tended to by a doctor. The quality of this tend directly impacts how fast they heal or build immunity.

Tend quality comes from three things, and room cleanliness is not one of them:

  1. Medicine potency. Herbal medicine sits at 0.6, industrial at 1.0, and glitterworld at 1.6. Each also caps how good a tend can be, at 70%, 100%, and 130%.
  2. The doctor's Medical Tend Quality stat. It starts at 20% and climbs 10% per Medical level, then gets scaled by the doctor's manipulation and sight. A doctor with damaged hands or bad eyes tends worse than their skill number suggests.
  3. The bed. A hospital bed adds a flat 10% and a vitals monitor another 7%. No other bed contributes anything, and bed quality does not affect tending at all.

Tending yourself costs you 30%, and every individual wound gets its own random swing of plus or minus 25% on top of all that.

Room cleanliness does matter, just somewhere else. It drives the chance a wound becomes infected, and it feeds surgery success. Keep your hospital clean for both of those reasons, but do not expect it to improve a tend.

When fighting diseases like malaria or plague, it is a genuine race between disease progression and immunity gain, and it pays to know which lever moves which side. Tend quality slows the disease down. It does nothing for immunity. What speeds immunity up is rest, worth about 10%, a hospital bed, worth about another 11%, keeping the patient fed and rested, and anything that raises Immunity Gain Speed. So the play that wins the race is a well-tended patient who stays in bed, not one who is tended well and sent back to work.

Surgery Success Rates​

Installing bionics or harvesting organs involves surgery, and surgery fails. Every failure, even a minor one, damages the patient, wastes the medicine, and destroys whatever you were installing. Outright death is a separate outcome rolled against the recipe's own risk figure and not a worse grade of the same failure, and the bill's info panel shows you that risk before you queue it. Success is capped at 98%, so no amount of preparation makes a surgery safe.

All four of these genuinely feed the success calculation:

  • Medicine potency. The biggest lever by a distance, and the reason herbal medicine wrecks operations.
  • Bed type. A hospital bed multiplies success by 1.10, an ordinary bed or bedroll by 1.00, and a sleeping spot by 0.70. Bed quality matters here as well, running from 0.9 at awful to 1.3 at legendary.
  • Cleanliness, which is where sterile tiles earn their keep. Their larger payoff is cutting infection chance, roughly 30% against a plain floor's 50%.
  • Light, which is a floor to clear and not a target to chase. Below 50% light you take a penalty down to 0.75, and from 50% upward it contributes nothing at all.

Operating in a slightly dirty bedroom with herbal medicine really is asking for trouble, though the medicine is doing most of that damage. With industrial medicine and a competent doctor you can reach the 98% ceiling on an ordinary bed, which makes glitterworld medicine most valuable in bad conditions and not in good ones.

Bionic Efficiency Limits​

Replacing biological parts with advanced bionics provides massive stat boosts, but there are diminishing returns.

A bionic arm has 125% efficiency against a natural arm's 100%, on a ladder running prosthetic arm 50%, wooden hand 60%, natural 100%, bionic 125%, and archotech 150%.

The catch is that an arm only carries half your manipulation. Each bionic arm is therefore worth about 12.5% manipulation and not 25%, so two of them put you near 125% and not 150%.

There is no hard cap above that, though. Manipulation is your limb efficiency multiplied by your consciousness, with nothing clamping the result, so a pawn with two archotech arms and slightly reduced consciousness still lands comfortably into superhuman territory. What consciousness damage does is scale the whole thing down proportionally without blocking you from high numbers. Budget for that multiplication, not for a ceiling, before spending thousands of silver on full-body modification.

Frequently Asked Questions​

What determines tend quality in RimWorld?

Medicine potency, the doctor's Medical Tend Quality stat, and the bed. A hospital bed adds a flat 10 percent and a vitals monitor another 7 percent, while ordinary beds add nothing. Room cleanliness is not part of it, despite how often that gets repeated. Cleanliness drives infection chance and surgery success instead.

How do I cure plague or malaria?

It is a genuine race between disease progression and immunity gain, but the two levers are separate. Tend quality slows the disease and does nothing for immunity. Immunity gain comes from rest, a hospital bed, and keeping the patient fed, so the patient who wins is the one who stays in bed, not the one who is tended well and sent back to work.

How do I stop surgeries from failing?

Medicine potency is the biggest lever, then bed type and quality, then cleanliness, then light. Light is a floor and not a target: below 50 percent you take a penalty, and above it you gain nothing. Success caps at 98 percent no matter what, so surgery is never risk free.

What happens when a surgery fails in RimWorld?

Every failure, minor ones included, damages the patient, wastes the medicine, and destroys whatever you were installing. Death is a separate outcome rolled against the operation's own risk figure and not a worse grade of failure, and the bill info panel shows you that figure before you queue it.

Are bionic arms worth installing?

Yes, though less than the headline suggests. A bionic arm has 125 percent efficiency against a natural arm, but an arm carries only half your manipulation, so each one buys about 12.5 percent. There is no cap above that, since manipulation is limb efficiency multiplied by consciousness, so archotech arms genuinely do reach superhuman numbers.