Used in the military and medical scene the abbreviation 'NKDA' means
No Known Drug Allergies.
sewn onto a patch and fastened to a soldier's gear, or scribbled on any plain surface
of his load out such as a helmet, knee pad or raid pouch flap.
This soldier has O POS+ NKDA scribbled
on his helmet, give him a gallon of morphine, STAT!