The Datura plant is one of the most beautiful, exotic, widely spread, toxic entheogens known; ingesting even a small quantity of Datura seeds or any part of the plant can cause strong delirium which can last up to 3-4 days.
There are several species of Datura and ALL of them will cause strong psychological and physical effects, most likely unpleasant and sometimes fatal: 95% of the Datura reports available describe the Datura experience as terrifying and many of them include caos, often involving the cops, violence, serious physical harm and, alarmingly often, trips to mental clinics and asylums.
VERY IMPORTANT!!! WE STRONGLY DISCOURAGE DATURA USE FOR ENTERTAINMENT AND TRIPPING PURPOSES ... Datura (as gorgeous as it is) is harmful for humans and animals, Tropane alkaloids are nothing to play with, its chemistry really messes up the human brain and body so please, please don't risk your health and your life. I believe that we must consider the consequences, benefits and risks of all the decisions we make and, unfortunately, the risks when consuming Datura are just not worth it.
I've read somewhere that the Ayahuasca shamans in central America warn people about the Datura shaman and his total insanity...

The most common species are
Datura Stramonium (aka Jimson Weed and Thornapple) and
Datura Inoxia (aka Devil's weed and Toloache), other species include
Indica, Metel, Willemsi, Sanguinea among many others.
As Datura is spread throughout most of the world, it has a long history of being consumed accidentally (or by people unaware of the dangerous effects of Datura, looking for a cheap high) causing many poisonings, some of them fatal.
One of the main causes of death due to Datura poisoning is that Tropane alkaloids are processed by the brain really slowly, and it can take several hours until the user feels the effect, so for example, when a teenager eager to get a "cheap high" ingests Datura and feels nothing after an hour, he'll ingest some more, ignorant to the fact that Tropane alkaloids haven't been processed by the body and, by the time he/she starts feeling the effects, the Tropane concentration on his/her body is so high that it will take his/her body maybe a couple of days to process the chemicals, always at risk of an overdose that will cause death.
The main active chemicals present in datura are the Tropane alkaloids
scopolamine, atropine, and
hyoscamine, all of them highly toxic.
Datura (or some of its Tropane alkaloids) are used in medicine today as a pain relief in really low quantities and women in some south american tribes use it as a labor aid.
The Datura plant has also been used in India, China, Africa, Europe and America for visionary and religious purposes for centuries: shamans believe that a great preparation, experience and strength is needed to live the Datura experience and handle its poisoning.
People have used Datura for evil purposes for centuries: it was given to virgins in some tribes mixed with an aphrodisiac so they contributed to their virginity loss by the white slavers, professional poisoners of all times have used Datura to make a fatal brew and it is even suggested that the FBI has experimented with Datura as a suggestive drug in interrogations.

Effects
According to the reports on Datura use and the studies made on Tropane alkaloids, when this alkaloids are consumed, you basically go nuts...
One of the main differences between the Datura plant and most of the "accepted legal highs" is that it causes delirium (anticholinergic delirium) and the user is completely unable to differentiate reality from fantasy.
People lose their memory, smoke imaginary cigarettes, talk to imaginary people, confuse the person they are talking to for someone else, cut themselves, go out to the streets, eat bugs... the list goes on and on.
Scopolamine, atropine, and hyoscamine cause:
- decreased heart contraction rate
- decreased heart contraction force
- vasodilation
- increased exocrine secretion (extreme sweating and salivation)
- reduction of intraocular pressure
- constriction of the pupil (these last 2 cause blurry vision for up to several days after Datura consumption)
(among others)
It is said that the Datura plant can cause permanent madness and there are reports of deaths for its irresponsible use... it is surprising that cultures from all over the world continue to use this plant and consider it a sacred plant.