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A drug for preventing infections before they take hold. Blocks malaria, sleeping sickness, plague.[sic] Must be taken every five days to remain effective.
This drug only prevents new infections. It does not cure existing infections - even those that are not yet discovered.

Base Stats

DrugMedical Drug
Market Value
18 Silver.png
Stack Limit
0.005 kg
Deterioration Rate
Path Cost


Maximum To Ingest


Crafted At
Drug lab.png
Required Research
Penoxycyline production
Work To Make
600 ticks (10 secs)
Resources to make
Neutroamine.png 2
Food Preference
Drug Category
Is Pleasure Drug

Penoxycyline is a drug that prevents users from catching any of the following potentially deadly diseases:

Note: Despite the wording of the description, it does nothing to prevent or treat infections, or any other diseases or ailments besides the three above. Penoxycyline also does nothing to treat pre-existing diseases, including diseases which have been acquired but have not yet presented symptom.


Penoxycyline can be crafted at a Drug lab once the Penoxycyline production research project has been completed. Each dose require Neutroamine.png 2 Neutroamine and 600 ticks (10 secs) of work. Its synthesis speed is dependent on the Intellectual skill, and crafting experience is attributed to Intellectual. Note that Neutroamine can only be obtained from traders or found in cargo pods.

It can also be bought from orbital, Outlander, or Empire Content added by the Royalty DLC traders, as well as Outlander and Empire faction bases.


Administering Penoxycyline provides true immunity against malaria, plague, and sleeping sickness over its ~5.556 day duration, preventing the protected pawn from catching the protected diseases. When the Disease event occurs, pawns that were protected from getting the disease by penoxycyline will be specifically noted as such.

It does nothing to stop a disease that has started and is already in progress. Since diseases have a hidden latent stage, taking penoxycyline during this stage will still allow the disease to take its course.

Similarly, it does nothing to prevent or treat any other disease or ailment beyond the three listed above.

While the in-game description says to "Take every five days", the effect actually lasts just over than a half-day longer, giving colonists some leeway to take the pills without acquiring a disease during the downtime of the effect as would happen if the duration were in fact 5.000 days and the colonist could not consume it promptly. Set a drug policy to tell the pawns to take one every 5 days and keep one in the inventory to take as soon as possible, or be cheap, set it to "6 days" and live dangerously.

Penoxycyline is not addictive and has no direct side effects. However Penoxycyline can contribute to overdoses, increasing severity by 0.08-0.14 per dose consumed. In comparison, hard drugs increase severity by 0.18-0.35. Overdose due to Penoxycyline are uncommon, as a pawn would have to consume a lot of it, however, it can increase the risk to overdoses when combined with hard drugs.

Version history

  • 0.15.1279 - Added as Malari-block, and only prevents Malaria
  • 0.16.1393 - Reworked. Renamed from Malari-block to Penoxycyline and now prevents a wide variety of infections. Cost decreased from 5 neutroamine to 3.
  • Alpha 17 - Cost is further reduced from 3 to 2 neutroamine. It also received an overhaul, such that instead of instantly boosting disease immunity to 61%, it now provides true immunity and cannot reactively increase immunity against a disease that is already in progress.