What Shakespeare put in his masterpiece actually contains some information about the most poisonous plant in the world. The tragic story of Romeo and Juliet by William Shakespeare is closely related to Deadly nightshade (Athropa belladonna).   In Hamlet, he mentions about curse of hebenon, which many scientists believe is Henbane (Hyoscyamus niger). And wild pansy (Viola tricola) in A Midsummer Night’s Dream.

Put this in any liquid thing you will, and drink it off; and, if you had the strength of twenty men, it would dispatch you straight”.

(Romeo and Juliet: Act 5, Scene 1)

On the internet, you can easily find information about poisonous plants in the world. But most of the information is still general for the plants around the world and not all of the plants actually we can find in Indonesia.

poisonous plant in the world
Painting art from Francis Sidney Muschamp

I am trying to find information in the Indonesian language, which gave the same result. only general information, not all of them are exist in Indonesia. Here I try to provide information that comes from my experience so far. and for sure, these poisonous plants are very easy to find in Indonesia.

Below Are The List of the 11 Most Poisonous Plant in Indonesia

1. Jarak pohon (Ricinus communis)

There are 2 types of Jarak pohon that are common for Indonesian peoples. The first is Jarak pagar (Jatropha curcas) and the second is Jarak pohon ((Ricinus Communis). Jarak pagar is famous for its oil content which has the potential to be a raw material for biodiesel. Meanwhile, the one we are discussing here is Ricinus communis, which has very poisonous seeds.

Ricinus communis
Jarak Pohon tree. The Seeds is containing Ricin compound

The most dangerous poison in the world extracted from this plant

The very deadly poison of this plant comes from its seeds. The compound called Ricin is a very dangerous poison. 6000 times more deadly than cyanide poison. And 12 thousand times more dangerous than the poison of rattlesnakes. This compound was first extracted by a scientist from Germany named Peter Hermann Stillmark. And then became very famous in the world.

Fortunately, this Jarak pohon is not popular as a cultivated plant in Indonesia. However, sometimes we can still find it growing wild in empty areas.  And so far there are no death cases report mention which caused by jarak pohon.

2. Ancar/Upas/Ipuh (Antiaris toxicaria)

After rumors and myths spread for a long time in Europe. Finally, there was a botanist named Thomas Horsfield (1773-1859) who first studied in detail about this plant to prove the myth. According to him, the sap lenders from the upas tree have a deadly effect.

Upas ipuh dangerous plant
Upas (Antiaris toxicaria)

Actually, since ancient times, the sap of this upas tree has been very well used as a poison. Upas itself in the local language means poison. The poison is rubbed on the arrowheads or blowgun by the people of Kalimantan, Sulawesi, and other eastern parts of Indonesia.

3. Gadung (Dioscorea hispida)

The tubers of Gadung contain high dioscorin and cyanide compounds. These chemicals are very dangerous and can be deadly poisons.  In Jogjakarta province, last year one family was poisoned by gadung and one of them died (published by Indonesian newspaper, Kompas.com, 12/08/2020).

There were many cases of gadung tuber poisoning have occurred in Indonesia. Actually, with proper processing, gadung is one of the alternative food as a carbohydrates source.

Gadung Diocorea
Tree, leaves, and tuber of Gadung

Indonesian Native plant

Gadung is one of the native South East Asia plants.  Herbaceous perennial lianas and produces tubers as a nutrient storage organ. Gadung tubers commonly become the raw material for some food products that are popular in Indonesia.

The most popular product is gadung chips. But if the processing method is not proper, it will risky because the toxic compound is still high. It plants is become one of the most poisonous plant in the world because of the frequent cases of poisoning that cause death.

4. Saga rambat (Abros precatorius)

The plants are herbaceous. Saga rambat leaves usually used to become an ingredient in traditional medicine. Saga rambat leaves contain glycyrrhizin which has an anti-inflammatory effect. Often used to treat canker sores, toothaches, and eyes cleaner.

legion botanica
Attractive seed color but poisonous

The red and black seeds are very attractive for decoration. But actually, these saga seeds can cause death. What’s dangerous about this vine saga is that it contains abirin which has a 75 times deadly effect from the ricin in castor beans. It only takes 3 mg of this substance to kill an adult human.

5. Pulus (Laportea stimulans)

Actually, if you asked me about, what is the most poisonous plant in the world? I will say Pulus. I have had a long interaction with Pulus while studying dangerous plant in Indonesia

In general, for stinging plants in Indonesia, we call it Jelatang. There are several Jelatang that can easily you can find in Indonesia, such as Pulus, Jancukan, Kemaduh, and Gympie-gympie in the Eastern part of Indonesia. Pulus is the most dangerous one. I have written details about pulus in the previous article. Please read here.

dangerous plant
Pulus (Laportea stimulans) is the most dangerous plant in the humid forest

Pulus is a member of the Urticaceae family. The plant is actually not spreading to all Indonesian islands. It is very easy to find in Sumatra and western Java actually. And from several experiences of being stung, the impact was different. Pulus that grows at an altitude of about 1000’s masl and in very humid environment is the most dangerous.  The trichome was full of the poisonous chemical compounds.

The longest record is 2 years in suffering

If stung by Pulus, the part of body which stung will feel a burning sensation for a long time. The first 3 days is the hardest phase because the burning sensation is felt continuously for 24 hours. The effect will fade away for 2 weeks.  The longest record I got is 2 months for the burning sensation totally disappear.

The longest-suffering I ever knew is 2 years. As I mentioned in the previous article. The woman who uses the Pulus leaves as her toilet paper is day by day in suffering. It was the reason why I put Pulus become one of the most poisonous plant in the world

6. Kecubung (Datura metel)

What we knew, that Kecubung is also one of the most poisonous plants in the world. The poison ability from kecubung has been often using for crime in some countries. In addition, teenagers also use flowers and seeds to get fly because of the hallucinogenic effects.

These hallucinogenic effects occur when consumed in relatively small amounts. The poison is actually very dangerous and deadly. Besides the hallucinations, the symptoms of poisoning can include redness of the skin, headaches, chills, seizures, and death.

Datura muryanto paiman
Datura tree with leaves and fruits

The toxic compounds contained in Kecubung include hoisin, oxalic acid, hyoscyamine, belladonna’s alkaloids, scopolamine, and atropine. The largest content of these compounds is in the seeds and the flowers. Generally, Indonesian peoples well recognize that Kecubung is one of the poisonous plant in the world

7. Rengas/Ingas (Glutha rengas)

from all the information on the internet, Rengas is not on the list as one of the most poisonous plants in the world. Even though this plant is very dangerous and easy to find in Indonesia. We can find Rengas in the swamp areas in the lowlands of Sumatra and Java.

This plant is a member of the Anacardiaceae family and is an important source of wood in Indonesia. Rengas wood is less popular with other woods. in several areas. Peoples use wood as a building material because the wood is durable.

In our village, we believe there is a resistance factor that determines whether a person is poisoned or not from rengas sap. some persons might hold it but the others, even when only standing under the trees, would have severe itching for a week. For this reason, I put Rengas on the list of the most poisonous plant in the world

the most dangerous plant in the world
Rengas sap is poisonous and dangerous for human

The sap can make you suffer

The most dangerous of these plants is the sap. When the skin is exposed to the sap of this rengas tree, the effect will be inflammation. Which causes itching and leads to infection which can then spread to other parts. Even when just standing under the tree, a person with poor immunity will immediately feel the impact.

Perhaps because it is less popular as a cultivated plant, which causes research on this plant is still very rare. Local peoples and farmers often use this plant sap as poison when hunting the animals or use it as a biopesticide in their rice fields.

8. Bitter Cassava (Manihot esculenta)

in general, there are two types of cassava plants, depend on the cyanide content. First, sweet cassava, which contains cyanide below 40 ppm and can be consumed directly. The second type is bitter cassava with has cyanide levels above 50 ppm. Bitter cassava types are generally grown for industrial raw materials.

Cassava cyanide
Cassava trees and tubers

Generally, what we must aware of for the cyanide compound is in the part of the tuber. Although in fact, all parts of the cassava plant contain cyanide compounds. But it is Ok when we find and eat is the sweet types. 

Some local foods from Cassava

The young leaves and tubers of sweet cassava are some of the delicious foods in Indonesia. Besides boiled cassava and fried cassava, lots of processed food comes from cassava tubers, starting from getuk, chips, tiwul, tape (fermented cassava), and others.

Then what about the high cyanide content in industrial cassava? In fact, the industrial material produced from cassava is an important commodity. such as tapioca, cellulose, bioethanol. The cyanide levels will drop dramatically in safe levels for consumption

9. Pakis cakar elang (Pteridium aquilium)

Pakis cakar elang or bracken fern is a part of the Tracheophyta family. It fern is a type of fern that is most easy to find in Indonesia. The young leaves of this fern are used as a vegetable. With a chewy and crunchy texture, the taste is quite delicious.

carcinogenic plant
Bracken fern has carcinogenic compound

The young leaves contain quite various nutrients and good for the health. Apart from being very high in natural fiber, the young leaves of bracken fern also contain high levels of vitamins A and C, potassium, magnesium, phosphate, and potassium, as well as high in protein.

Ptaquiloside is carsinogenic compound

What makes bracken fern dangerous is its high content of the compound Ptaquiloside. The report by the researcher in the British Journal of Cancer, mention that the compound is carcinogenic. Other researchers from Japan also reported similar results regarding the potential of Ptaquiloside compounds in increasing tumor cell development in mice.

The presence of Ptaquiloside is the reason why bracken fern become one of the poisonous plant in the world. But don’t worry, the Ptaquiloside compound will actually be degraded when cooked first. Ptaquiloside is not heat resistant. When choosing this fern in the vegetable menu, just cook them first to avoid risks.

10. Bintaro (Cerbera odollam)

When you are on the toll road or city park in Indonesia, it is almost certain that you will easily find Bintaro plant. Its plan is famous as shade plants almost in all urban areas. In general, Indonesian peoples understand that the fruit is not edible. But it seems that there are still only a few peoples who know that this plant is very poisonous

Bintaro poisonous plant
Bintaro (Cerbera odollam)

The content of poisonous compounds from this plant is in all parts. However, the highest toxic content comes from the seeds. Cerberin are compounds that can inhibit calcium ion channels in human muscles so that they can interfere the heart performance and cause death.

From several studies, also stated that Bintaro is a plant with a very strong allelopathic effect. When other plants grow near Bintaro, the allelopathic compound will inhibit the growth.

11. Gympie Gympie (Dendrocnide moroides)

This plant is common in Australia. However, several reports have obtained information that this species is also found in Maluku. This is quite logical because Maluku and Australia are located in the Weber Line region which has similarities in terms of flora and fauna diversity.

gympie poisonous plant
Gympie-gympie (Dendrocnide moroides)

In general, the poisonous compounds from stinging plants of the Urticaceae family are tryptophan, histidine, alkaloids, flavonoids, formic acid, and Anthraquinones. When our skin is exposed, the effect is a burning sensation. As same as when our skin is exposed to pulus

Daun Gatal vs Gympie-gympie

Daun gatal is one species in the Binaiya mountain in Maluku. One of the Stinging plants from Urticaceae. Local peoples often use the leaves as a relief from aches after a trip. But it seems this is a different species.

Unfortunately, no information available regarding these two species comparison or studies. Are daun gatal actually the same as Gympie-gympie or a different species. Regarding the names of different species, Urticaceae is very confusing. It is evident that several species in this family have many synonyms.


These are some of the most poisonous plants in the world, I can collect so far. They are can be easily found in Indonesia. Hopefully, the information is useful. But if there are things that need to be corrected or discuss, please inform me in the comment’s column.

Muryanto Paiman

always love to learn from nature.  Passionate on studying plants in some aspects: the DNA, Identification, propagation, and their uses


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