Hallucinogens contain nitrogen and are classified as alkaloids. There are various types of hallucinogens. Much of them have chemical structures like natural neurotransmitters. Various type of hallucinogens acts differently. The effects are not clear about exact mechanism of every types of hallucinogens.
Some hallucinogens can be found naturally (e.g., trees, vines, seeds, fungi and leaves) and others are made in laboratories.
Hallucinogens drugs work as drugs and sometime no completely. These drugs work temporarily interfering with neurotransmitter action or to their receptor sites by binding.
Four common types of hallucinogens:
1. LSD (d-lysergic acid diethylamide/ lysergic acid diethylamide)
2. Peyote
3. Psilocybin (4-phosphoryloxy-N, Ndimethyltryptamine)
4. PCP (phencyclidine)

How abused
Hallucinogens are used use into ritualistic or spiritual traditions. The effects of hallucinogens are highly variable and also unreliable. Hallucinogens produce different effects in different people at different times. Use hallucinogens can be very dangerous because of their unpredictable nature.

Brain and Hallucinogens
Under influence of hallucinogens, people see many things are not real. For example, they see images, hear sounds, and sometime feel sensations. Some hallucinogens also produce rapid, intense emotional swings. These drugs cause their effect by initially disrupting the interaction of nerve cells and the neurotransmitter serotonin. Hallucinogens contain drugs are distribute throughout the brain and spinal code. The serotonin system is involved in the control of users behavioral, perceptual, and regulatory system. It also controls mood, hunger, body temperature, sexual behavior, muscle control, and sensory perception.
PCP acts differently than others. Like glutamate receptor in the brain that plays important role for the perception of pain, responses to the environment, and learning and memory.

Because of no proper controlled research studies on the specific effects of these drugs on human brain. Some studies and case reports have been showed some effects associated with the use of hallucinogens.

Treatment
This treatment is usually supportive. Type of treatment is supportive provision of a quiet room with little sensory stimulation. Sometime benzodiazepines are used to control extreme agitation or seizures.