APTX 4869

APTX 4869 is a fictional poison in the anime and manga Case Closed.

The toxin is a derivative of an experimental immortality formula, adapted by Sherry to function as an untraceable, lethal poison.

APTX is an abbreviation of "Apoptoxin," and, as the name implies, it involves the activation of uncontrolled apoptosis which causes death by the destruction of cells. In addition, it can also activate telomerase.

The poison is designed to be untraceable in its victims. However, in very rare cases, it causes the apoptosis of non-neural cells only and the apoptosis would stabilise at some point, causing the victim's apparent age to be decreased. Conan Edogawa, the series' protagonist, is such a victim; later Shiho Miyano, who chooses to attempt suicide by using her own drug, was added to the very short list of people not killed by APTX-4869.

Throughout the series there are several instances in which the APTX was temporarily neutralized and Shinichi and Ai/Shiho were returned to their actual age forms. The main ingredient for this reversal is a component found in Chinese ginseng root schnaps, which Ai has already incorporated in a prototype - and as yet non-permanent - antidote for the APTX. It is to note that in the instances where Shinichi or Ai changed back, the recipient was suffering from a common cold while the component was ingested, indicating that the immune system somehow has to be taxed for the antidote to work.