1. Taking medication of some kind. Is the patient on anything that might interact negatively with the treatment drugs? My doctor put me on steroids to treat my hay fever.
2. Experiencing the physiological or psychological effects of some illicit or recreational drug. He's acting so weird. Do you think he's on drugs? I watched the movie on acid, and it was one of the most mind-blowing experiences of my life! The athlete was disqualified when it came to light that he was on speed during the race.
See also: on
Currently taking medical drugs that have been prescribed by a doctor. Are you on any medication that would inhibit your ability to operate heavy machinery? I'm willing to go talk to a therapist, but I don't want to be put on medication, got it?
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.
taking medicine for a current medical problem. I can't drive the car since I am on medication. He is on medication and hopes to be well soon.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.