How long do you have to cook Chaya for it to be safe to eat?

We’ve started growing Chaya based on ECHO’s recommendation, but we’re unsure how long it needs to be cooked before it is safe to eat. Do the different parts of the plant need to cook more or less, some of the people near where we live eat the stems as well as the leaves.

To safely remove the toxin, boil chaya leaves for 10 to 20 minutes in a non-aluminum pot.

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This document explores the research of cooking times on Chaya.

With raw, uncooked material, HCN was detected in leaves and petioles but not the green stems. No HCN was detected—for leaves, petioles, and stems—20 minutes after boiling. In a subsequent replication, however, HCN was detected the following day, after boiling leaves, petioles and stems. It took between 15 and 20 minutes of boiling before HCN was no longer detected. Results suggest that leaves, petioles and green stems should all be boiled to remove HCN.

Happy cooking!

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Hi Danielle
I am a new member of Echo. I started with Chaya in 2011 on my property. I have over 2500 trees and 3000 in my Nursery. I love Chaya, but I use it diffenent, I cut my leaves into 25mm strips and dry in self made solar dryers. The last 5 years I did lots of research and development of Chaya dried leaves. I founded that it one of the best meat tenderizer I ever used. I love my meat and the good about it, it increase the nutritional/health value of the meat. I use the dried leaves in all my dishes, Chaya is my “Life” because it saved my life from diabetes. I use Chaya dried leaves in all my food dishes.
I am feeding my geese the raw stems of the Chaya for the last 5 years and they are so healthy it is unreal. If the HCN levels is high why do they not get sick or die?
I find useful information on Echo website to test the HCN on Chaya, I will test it on the dried Chaya leaves.
Chaya Greetings


Hi Rian,

I look forward to hearing about your testing the HCN in your chaya. Blessings on your work.



Thanks so much for the work you do and for sharing with us! We’re excited to see what your testing shows!

I’ve done a little literature searching and trying to figure toxicity out, but not a lot of direct definitive amounts are labeled.

This is a summary of what I have found for humans: Leaves of tropical crops like chaya (Cnidoscolus aconitifolius) and cassava (Manihot esculenta) contain cyanogenic glycosides, toxic substances that release hydrocyanic acid (HCN; also referred to as cyanide or prussic acid) when cells are crushed. Consuming plant parts that contain cyanogenic compounds without cooking them can cause cyanide poisoning, with effects that vary depending on cyanide levels and how long a person or animal has been eating that plant. Different ‘safe levels’ have been stated from various sources. The Agency for Toxic Substances and Disease Registry (ATSDR) recommends an allowable daily intake value of 0.05 mg/kg body weight (ATSDR 2006). I was able to find one source that recorded 270-420 mg/kg HCN in fresh chaya leaves (Ross-Ibarra and Cruz 2002). This would mean that a 70 kg (154 lbs) person could safely consume 8.3-12.9 g fresh chaya leaves daily which is roughly 3-6 fully expanded leaves (I weighed 3 samples). A 20 kg (44 lbs) child could only consume 2.4-3.7 g fresh chaya leaves daily which is roughly 1-2 fully expanded leaves depending on size. This is not very much and doesn’t seem like a good idea to regularly do without being extremely careful about how much you intake. An individual’s body’s ability to process and remove the toxin may depend on other nutritional aspects like a certain level of health or levels of water or proteins in the diet. There is a lot of uncertainty.

For animals: Certain livestock, such as fowl, can potentially handle higher amounts of CN in their feed. Perhaps drying the chaya leaves reduces the HCN content of the leaves to an even safer level? We would love for some research do be done and shared about this!! It has been looked at as a component in poultry feed (see articles referenced below). At ECHO, we do often feed it to our fowl (chickens and ducks) and have not seen any negative side effects yet.

Cyantesmo paper can be used as a simple cyanide screening test and is available from [CTI Scientific]​ ​( One roll supplies enough 2.5-cm long paper strips for 200 tests. The test is mainly done to determine absence or presence of HCN. The darker the blue, the more HCN present, but this test will not indicate exact parts per million. ​ ​

ATSDR (Agency for Toxic Substances and Disease Registry). 2006. Toxicological profile for cyanide. Atlanta, GA: U.S. Department of Health & Human Services, Public Health Service.

Ross-Ibarra, J. and A. Molina-Cruz. 2002. “The Ethnobotany of Chaya (Cnidoscolus Aconitifolius ssp. Aconitifolius Breckon): A Nutritious Maya Vegetable.” Economic Botany 56 (4): 350-65. doi:10.1663/0013-0001(2002)056[0350:teocca];2.

Research article abstracts on chaya leaf meal fed to poultry:

Donkoh, A. Kese, A.G., and C.C. Atuahene. 1990 Chemical composition of chaya leaf meal (Cnidoscolus aconitifolius (Mill.) Johnston) and availability of its amino acids to chicks. Animal Feed Science and Technology 30 (issues 1-2): 155-162 URL:

Kese, A.G., Donkoh, A., Atuahene, C.C. and C. Nkansah. 1989. Evaluation of methods of processing chaya leaf meal (CLM) in terms of chemical composition and on performance and physiological parameters of chicks. Nigerian Journal of Animal Production Vol 16 No. 1 URL:

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Dear Stacey
I appreciate and thank you for the information you send me.
Just in short, South Africa had no Chaya plants. After a long research I discovered a person who was working for Echo and now living in SA as a missionary, had one Chaya tree that he brought from Echo with him, the Chaya „Estrella, verity. I got 100 cuttings from him in 2010 and in return donated money to the organisation.
I was diabetes Type2 and want to see what effect the Chaya would have, using myself as a human trail. My body was in a very bad stage of the side effects from diabetes. Today I live a normal healthy life due to Chaya and grow Chaya trees on a large scale. I develop products from Chaya and also provide the hunger people in rural poor areas with trees for home use and also do job creation from Chaya at the bottom of the pyramid.
I processes Chaya in a different way then what research show on the web. I am eager to test my final product HCN value, but I cannot find any Cyantesmo test paper in South Africa. I tried contact in the USA via e-mail but without any success. I only need a couple pieces.
My processing of wet Chaya leaves ( I only use the leaves, not the stems) is as follow. I only use the final product in all my products and food/meat dishes.
 Wash the wet leaves and then cut it into 2.5cm strips
 Wash the strips again in new water
 Pack the strips into drying trays
 The trays then go to ventilated solar dryers, depending on the sunlight and temp it takes about 6 hours to dry. The dried leaves stay green and are easy to crush in smaller pieces or powder.
 The solar dryers are covered with UV protected clear corrugated sheeting.
I want to test the Chaya Dried leaves HCN. When you use the dried leaves only to cook, there is no smell of HCN. As soon I get hold of the HCN test paper I will use the technique that Echo used

Wow! What amazing results you have seen. I’m hopeful that chaya can continue to help restore bodies and health through your encouragement and promotion of your dried powder!

I am sorry they haven’t gotten back to you yet at CTL. Please let me know if they don’t get back to you via email in a few days and perhaps I can call them to see what the shipping and payment procedure is for the cyantesmo strips. I went to the stock item on their website and added it to my cart, selecting South Africa as my country and it didn’t seem to reject it. So hopefully they can send it to you.
Unfortunately, like I said before, it does not quantify the ppm of cyanide in the leaf tissue. It does indicate HCN that vaporizes from the plant tissue though and is the simplest detection method we have found. So if you decide to use the strips, all you have to do is put the strips in a plastic bag with some of your powder and leave it in the sun. The heat will cause some of the plant cells to rupture and release HCN to be detected. If there is HCN in your leaves, it will turn the strip blue! I tried this with some dried powder given to me from a network member in Guatemala and the strips did turn blue, but we don’t know how much HCN is in that powder or how they processed it.

We have partners who are working with a spectrometer and the test strips to create a curve that would tell us approximate ppm based on the darkness of the shade of blue. That would help a lot! If you do have access to a University in your area, you could potentially send them a sample of your powder that they could analyze via spectroscopy and let you know exactly how much CN you have in the leaf tissue iteself.

We are excited to see how the technique works for your product!

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Thank you. I develop already a couple of Chaya products. That only gives positive feedback from the clients. My e-mail to them was read by
Henry Medollo but I had no reply or any feedback from him.I need only a few strips not a roll, just to see the results on the dried powder.
I would like to send you the pictures with descriptions of my drying process but how do I upload it on Echo site? Or can I send it to you via e-mail. It is my passion to test it, and share it if the results are good. In South Africa it is impossible to ask Universities to analyse it, you must know somebody there to test it in secret. I already tried and also with private companies.
They are all controlled by the SA medicinal council to protect the pharmaceutical companies. They are afraid that indigenous medicinal plants will have an effect on their big money making business. I am “allowed” to sell my products but must keep it on a low profile, due to my skin colour. Sorry about this but I have no problem with any skin colour person, they are my best friends. To must have seen the political situation in our country on TV.
I will follow the instructions you provided as soon as I can get the test strips. I am implementing a project to plant 1 million Chaya trees in the poor rural communities and teach them how to dry the leaves to have a food supply all year round. I just want to provide them with the best information on Chaya.
I know Chaya is drought resistance but I implemented a water collecting technology that the rural communities can use to grow their other vegetables all year round and do not have to wait for the rainy season. It is very effective on Chaya, I use it due to water problems on my farm.
Thank you for your excellent assistance and help.

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Thanks Amaya for Your Tips :slight_smile:

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Just wondering if there is an update on the chaya testing and chaya development farm.

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Related to cooking chaya, I read people saying it needs to be boiled but does the water need to “vent” allowing the HCN to escape in the steam or is the heat alone enough to break down the HCN? I am asking because we do most of our boiling in a pressure cooker to save time and fuel. Most of the time, the pressure cooker sits cooling until someone has time to open it. By then, the steam is normally gone. Is the HCN gone too?

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Today I enjoyed my lunch with Chaya with Ugali,The Echo people from Arusha Tanzania visited the school am teaching for training and finally they prepared Chaya for our students.They told us when boiling chaya the boiling vessel should be opened so as to allow the acid to evaporate for about 30 to 40 minutes.
I like it

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Hey Glen!

I’m more than happy to explain the chemistry. Chaya and Cassava contain the same cyanogenic glycoside and there has been a lot of research poured into cassava processing techniques. Linamarase, the enzyme that removes the cyanide compound from the cyanogenic glycoside becomes active in water. The cyanohydrin will stay in the water until conditions allow for it to off-gas as HCN (Montagnac et al., 2009; figure 1). These conditions are a pH greater than 4 and a temperature of 30°C (86°F).

When processing chaya leaves, you do need to allow the vapors to be released because the cyanide off-gasses as HCN. Normally that just means leaving the lid off during cooking, but you can’t do that in a pressure cooker! I would recommend you cook the chaya separately and add it to the pressure cooker contents at the end. This may also retain more nutrients as chaya only needs to be cooked for 15 min.

You could try right after cooking, to take the pressure cooker lid off and add a bit more water. Letting the pot sit warm for at least 15-20 min after cooking, making sure that there are vapors coming off. The temperature doesn’t actually have to reach boiling for the HCN to be off-gassed. We can’t be positive though without testing so ECHO can’t confirm that this method would remove CN as we have not trialed this method.

Montagnac, J.A., C.R. Davis, and S.A. Tanumihardjo. 2009. Processing Techniques to Reduce Toxicity and Antinutrients of Cassava for use as a Staple Food. Comprehensive reviews in food science and food safety. 8:17-27.

As always, great info Stacy. Much appreciated. Glen

Thanks, This was extremely helpful. The best explanation so far. I would love to know if there is enough off-gassing by making chaya chips in the oven, much like we would make kale chips.

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