Abrus species are the most poisonous plants in the world. The glycoprotein Abrin (agglutinin, toxalbumin) is a potent plant toxin: microgram quantities are suficient to kill a man, and just like ricin lectin poisoning there is no antidote (see Abrus precatorius L., inchem.org). Merck 12th Edition describes Abrin as "a toxic lectin and hemagglutinin obtained from the seeds of jequirity, Abrus precatorius L., Leguminosae, a common vine of tropical countries, also found in central and southern Florida."

Note that the word "abrine" refers to a totally different chemical, N-Methyl-L-Tryptophan and the two should not be confused. Some sources (including this page in previous versions) write Abrin as 'abrine' although this should be avoided.

The protein binds to the rybosomes in the cell and prevents it from producing proteins. A person dies within 4-5 days with symptoms of hemorrhagic fever. There is some history of use in traditional medicine and DMT has been found in the seed / bean. The following is a potentially confusing quote from Alexander Shulgin who mentions that Abrine (N-Methyl-L-Tryptophan) is also found in the Abrin-toxin producing A. precatorius seeds. From Ask Dr. Shulgin:

"N-Methyltryptophan (L-(+)-Abrine, or simply Abrine) is widely distributed throughout the plant world. It is a major component of the Rosary Pea (the Jequirity Bean) which has the botanical name Abrus precatorius and which has enjoyed some popular use as an insecticide. The toxicity of this rather poisonous plant is apparently not in its alkaloid composition but in its protein fraction. Abrine itself has shown some tumor inhibition properties in rats, but the search for possible pharmacology was disappointing.

But be careful. The name "Abrin" is quite a different item. It is an extremely toxic protein from this same plant. The seeds of this plant have been used for poisoning people, and are very nasty. N,N-Dimethyltryptophan has also been found in the Jequirity Bean seeds and several other plants, but other than having being described as a plant growth inhibitor, it is unknown pharmacologically." -- Dr Alexander Shulgin, Sep 19 2002

Cooking it will destroy the toxin, but if the inside of the seed is deoleated by acetone and then ground you will get one of the five most potent biochemical weapons known to man. This plant is not for playing around! Abrine's toxin is fourth, only behind the botulinum, schigella and tetanus toxin.

Comparative Lethality Of Selected Toxins And Chemical Agents in Laboratory Mice
David R. Franz, DVM, PhD, Colonel, Veterinary Corps, UNITED STATES ARMY
AGENT	LD50   (mg/kg)	MOLECULAR WEIGHT	SOURCE
Botulinum Toxin	0.001	150,000	Bacterium
Shiga Toxin	0.002	55,000	Bacterium
Tetanus Toxins	0.002	150,000	Bacterium
Abrin	0.04	65,000	Plant (Rosary Pea)
Diptheria Toxin	0.10	62,000	Bacterium
Maitotoxin	0.10	3,400	Marine Dinoflagellate
Palytoxin	0.15	2,700	Marine Soft Coral
Ciguatoxin	0.40	1,000	Fish/Marine Dinoflagellate
Textilotoxin	0.60	80,000	Elapid Snake
C. perfringens toxins	0.1-5.0	35,000 - 40,000	Bacterium
Batrachotoxin	2.0	539	Attow - Poison Frog
Ricin	3.0	64,000	Plant (Castor-Bean)
Conotoxin	5.0	1,500	Cone Snail
Taipoxin	5.0	46,000	Elapid Snake
Tetrodotoxin	8.0	319	Puffer Fish
alpha-Tityustoxin	9.0	8,000	Scorpion
Saxitoxin	10.0 (Inhal;2.0)	299	Marine Dinoflagellate
VX	15.0	267	Chemical Agent
SEB (Rhesus/Aerosol)	27.0 (ED50 ~pg)	28,494	Bacterium
Anatoxin-A(s)	50.0	500	Blue-Green Alga
Microcystin	50.0	994	Blue-Green Alga
Soman (GD)	64.0	182	Chemical Agent
Sarin (GB)	100.0	140	Chemical Agent
Aconitine	100.0	647	Plant (Monkshood)
T-2 Toxin	1,210.0	466	Fungal Mycotoxin
Source: http://www.usamriid.army.mil/education/defensetox.htm