Antifreeze is a substance used to prevent things from freezing, common for use in air conditioning units. However, antifreeze is a poison that can be very deadly or fatal when ingested. The time it takes for a person to die after ingesting antifreeze varies. It can occur in just a few hours or may happen over a period of several days. Even a small amount of antifreeze can cause a very painful death, coma, or serious injury to the body. Anyone who has ingested antifreeze will need to seek medical attention immediately to help stop the devastating effects that this poison can cause.