What is the medical term meaning adverse reaction to treament?

The medical term for an adverse reaction to treatment is adverse event.

Here are some other terms you might encounter:

* Side effect: A predictable and often unavoidable consequence of a treatment, usually less serious than an adverse event.

* Adverse drug reaction (ADR): A negative reaction to a medication.

* Drug-induced injury: An adverse reaction to a medication that results in harm.

* Medication error: A mistake in the administration or prescribing of a medication.

It's important to note that the terms "adverse event," "side effect," and "adverse drug reaction" are sometimes used interchangeably, but they have distinct meanings.