OD is a medical abbreviation that can have different meanings depending on the context. Here are a few possible interpretations:
OD can stand for "right eye" (oculus dexter) in ophthalmology, which is the field of medicine that deals with eye-related conditions. The left eye is commonly abbreviated as OS (oculus sinister).
OD can also stand for "overdose," which refers to taking an excessive amount of a medication or substance that can cause harm or even death.
In some contexts, OD can be short for "once daily," which is a dosing frequency that means the medication should be taken once a day.