Hallucinogens can be naturally occurring or produced by a chemical process. They come in a wide variety of forms from plants to small tabs of printed blotting paper, tablets, and powders.
Hallucinogens act upon the central nervous system to cause radical changes in sensory perception, causing people to see, hear, and feel things that are not real. Users may experience intense sensory perception, a mixing of senses, confusion and a distorted self image.
Physiological effects include rapid heart beat, chills and increased blood pressure.
Some people using hallucinogens may experience vivid but negative hallucinations, extreme feelings of panic and anxiety, and paranoia.