1. A specific compound or mixture which, when administered, which prevents or retards the absorption of a poison: "In the laboratory, the scientist developed a mechanical antidote for the virus that was spreading among the cattle in the area."
2. A remedy to counteract the effects of a poison or toxin: "The ambulance driver administered the mechanical antidote to the snake bite victim to retard the effects of the toxin during the trip to the hospital."

"The mechanical antidote is administered by mouth, intravenously, or sometimes on the skin, and it may work by directly neutralizing the poison."