It is sometimes claimed that a drug called Ketamine can produce all features of the near death experience.
Here's my Rebuttal
There is some big differences between ketamine and near death experiences such as you need lots of brain activity for ketamine to work while people with very little still have near death experiences some report accurate information and see things while outside their body some even from very far distances away.
Another difference is too ketamine experiences are often frightening. Unlike the vast majority of near death experiences.
DMT Chemicals Causing NDEs
DMT does not account for the Veridical Elements of the NDE, nor the amazing structure of many NDEs, accourding to the book DMT: The Spiritual Molecule, it may act as an initial NDE trigger, but cannot make up for the entire experience, Veridical Elements and all, in addition to the pesky little fact that within 4 to 20 seconds of cardiac arrest, the brain waves go flat, and even if they were sufficient (which they are not), the brain cannot produce images in this state, and even if it could, you couldn't remember them.