Which term best describes a remedy for a poison?

The term that best describes a remedy for a poison is "antidote." An antidote specifically refers to a substance that counteracts the effects of a poison, acting directly to neutralize or mitigate its harmful effects on the body. It is designed to provide a targeted response to intoxication, making it an essential tool in medical treatments for poisoning.

While "cure" suggests a general healing or correction of a condition, and "elixir" typically refers to a sweetened liquid used to administer medicine or as a magical solution, these terms do not specifically denote a remedy for poison. "Counteraction" describes an action taken to oppose or act against something, but it is not a formal term used for substances that neutralize poison. Thus, "antidote" is the most precise term in this context.