If you check out website amaranthus, I'm sure you can find something on it to answer your questions.

Recently I purchased a bag of amaranthus flour from The Whole Foods Store. I haven't used it yet, but am looking forward to trying it.

I'm not surprised about the Amaranthus flour, Itcollins. One thing I found on the web is that the seeds can be popped like popcorn or ground into flower, and they are not a part of the plant that is iffy like the older stems and leaves.

We have been eating the amaranth greens for two or three years and they don't seem to be hurting us. We freeze them for winter use too. A friend from Jamaica calls it "calaloo" and showed us how to prepare the stems too which I liked better than the leaves.

Maybe you are thinking of the fact that amaranth contains oxalic acid, like spinach, which prevents the calcium from being used by the body? Nutritionists generally recommend limiting greens with a high oxalic acid content. I'm sorry I don't remember excatly how much they say to eat in a weeks time. These greens with the oxalic acid are great sources of other nutrients, just don't depend on them for your calcium.
VG

Cook the amaranth greens by boiling in water and discard the water before eating.This is how oxalic acid will be removed from leafy vegetables.It is a good sustitute for spinach. Cooked amaranth leaves taste like cooked spinach.Select the tender leaves for consumption.
People having kidney problems should stay away from green leafy veggies. because of oxalic acid.

I have eaten amaranth (pigweed) greens a lot over the years, and have never noticed any problems. They are very
nutritious and a close relative of our modern spinach, beets, etc. The Chinese use a type of amaranth (I have grown it before), and call it "Chinese spinach."
It can either be boiled or stir-fried with oil and garlic.
Also good to mix with other wild greens, like lambs quarters, curly dock, etc. I can't imagine under what situations these greens could be called poisonous.??

i think that the possible poison could be from its tendency to accumulate Nitrogen...which is harmful in excess...i believe it to be safe, as long as you are not eating pounds of it everyday

red streaks on the stem mean higher in nitrates...

I'm 57 and have been eating Amaranth for more than 50 of those years. If you have a problem with spinach then amaranth might bother you, or if you are taking some kind of prescriptions nitrate, otherwise don't worry.

Perhaps you referring to epazote. Epazote characterizes the taste of Mayan cuisine in the Yucatan and Guatemala. The name "epazote" comes from the Nahuatl words, epote, meaning disagreeable or foul, and epatzotl, meaning "sweat," reflecting its strong aroma.

Mexicans and Central Americans use epazote fresh in salads, soups, and meats and especially to enhance huitlacoche, mushrooms, bean- and chile-based foods such as refried beans (frijoles refritos), frijoles negros, moles, or rice and beans. It is usually added toward the end of cooking to prevent bitterness in the finished product. Spaniards flavor teas with epazote.

Aha, finally I see some of the tendency that prevents most people from eating mushrooms also affecting the situation with a plant's edibility. Apparently some of the species of the large genus Amaranthus are less easily digestible than the others. My guess is that the tender young pigweed greens are safe and even more safe if cooked. Certain people may be sensitive to them, the same people probably wouldn't be able to eat sorrel (=sour dock). When I was ~3, I once became sick from eating too much fresh sorrel leaves. But that really was an immoderate amount. Another guess is that someone somewhere consumed too much pigweed greens on an empty stomach, got sick and started spreading the word that it was toxic. That is what often happens with wild mushrooms species which are not edible raw anyway.

My mother in law eats these all the time. It is poisonous to some livestock, so I wonder if this is one reason why they are labeled as such? My mother in law grew a variety in China that had a purplish tone and we cooked some this summer and they were all right. They taste like spinach to me and I'm not a big fan of cooked spinach. She also says you should eat the young tender ones especially before the seed pods form. I had some neighbors that were in the nursery business and they said that the type we all had in our yards was naturalized offspring from the variety the vietnamese had grown when they had planted their gardens.

As best as I can tell, the toxicity of pigweed that most people hear about are primarily in ruminants (cows) due specifically to the plant's nitrate-absorbing qualities, and the ruminant's ability to convert nitrate into nitrite.

UPenn.edu says this about pigweed (amaranthus spp.):

Toxicity: as a salt, nitrate is toxic for ruminants at 0.5 g/kg (single oral dose). Forages containing > 0.2% nitrate and water containing > 1000 ppm are potentially toxic. Plants can accumulate 3 to 4% nitrate under appropriate conditions. Nitrate is not very toxic for monogastrics since it is not efficiently reduced to nitrite. However, nitrite is toxic for monogastrics. Unlike cyanide, nitrate does not volatilize and therefore dried forages are toxic.

Here is a link that might be useful: PigWeed

Pigweed is commonly known as the "careless weed" and is viewed with disdane by the uninformed, such as I. It gets its name from the fact that it is a favorite of the pigs. I did not relize that humans could use it/eat it.

What you guys called pigweed(amarathus), we Asian eat it all the time. Just use the tender leaves and tips and stir fry plain or with meats. Be warn tho, the liquid release from it will be reddish. There is one commonly cultivated variety commonly called Chinese spinach with big broad leaves that are excellent for stir frying or salad. We even eat plants in the night shade family that are known to be toxic such as the garden huckleberry of the wild and the cultivated species.

Yes, we Asians eat it all the time. Someone wrote correct, just throw away the first boil water. Known as Kach Mach ka saag.

I cook pigweed like a spinach. Steam all but roots and woody stems (young ones okay). Then add butter, salt and pepper. Yum! Even my 15 year old son loves them.

I just finished a bowl of brown rice, Quinoa and Amarath with a bit of sea salt and garlic powder. It was delicious and nutritious I eat it once a week and have never had side effects.

Interesting. I have eaten amaranth both the cultivated Asian ones and the wild ones. If they were poisonous I would be dead 100 times over. The "cultivated ones " are the ones you can buy seeds in the seed catalog Asian section. Normally leaves are light green, green with maroon veins or now they have a maroon/purple leafy one. Planted that last summer and very tender when young. The wild one is the one referred to here as a weed aka pigweed (although I do not agree with the description. A weed is a plant out of place, so anything in the right environment can be a weed if it does not belong there at that time).Anyway perfectly healthy to eat. Only draw back is that the wild one has a more earthy taste compared to the cultivated Asian varieties. The leaves also might have small hairs so raw eating does not sound appetizing but sauteed they are pretty good.