nil per os

English Wikipedia has an article on:

nil per os

Wikipedia

From Latin nil (“nothing”) + per (“by means of”) + os (“mouth”), literally “nothing by mouth”.

nil per os

1. (medicine) Nothing may be eaten or drunk.
   • 1971, Diabetes Mellitus: Diagnosis and Treatment, volume 3, American Diabetes Association, page 252:

     The initial written orders should include: insulin dosage to be administered as soon as the patient appears nil per os, measure all intake and output, and obtain venous blood for measurement of blood or serum urea nitrogen, glucose, acetone [...] and phosphorus.

   • 1998 June, DeMeo, M et al., “Beneficial effect of a bile acid resin binder on enteral feeding induced diarrhea.”, in The American Journal of Gastroenterology‎^[1], volume 93, number 6, Elsevier, Abstract:

     We evaluated the effect of Colestid on enteral feeding-induced diarrhea in a double-blind placebo-controlled study. Nineteen patients who were nil per os (NPO) for 5 days before initiation of enteral feeding were enrolled in the study and treatment continued for 7 days.

   • 2021 April, Couloures, K. G. and Hertzog, J. H., “Adverse Events: Risk Factors, Predictors, and Outcomes”, in Mason, Keira P., editor, Pediatric Sedation Outside of the Operating Room: A Multispecialty International Collaboration, Springer International Publishing, →ISBN, page 669:

     Table 34.3: Nil per os odds ratio

• NPO (initialism)
• nil by mouth
• nill per os (typographical error)