What is E Jiao?

E Jiao is a solid glue-like block made by simmering donkey hide for a long time until it becomes a thick gelatin, which is then cooled and set. It is a single-substance Chinese medicine, not a mixture, and it is also sold as Donkey-Hide Gelatin or Ass-Hide Glue. In Chinese medicine it is one of the best-known "blood tonics", given for pale skin, tiredness, dizziness, light periods and dry coughs.

Today it is used mostly by people who feel run down after illness, blood loss or heavy periods, and by people going through chemotherapy who want extra support. It is also a popular ingredient in sweet ready-made cakes and drinks sold as tonics.

On the evidence: E Jiao has a very long record of traditional use, but good-quality human trials are lacking. Traditional standing and proof of effect are two different things, and that difference applies everywhere in this document. If you are tired or pale, the useful first step is a blood test, not a tonic.

How does E Jiao work?

Nobody has shown clearly how E Jiao works in the body, and honest sources say so.

E Jiao is mostly collagen protein that has been broken down by long cooking. When you eat it, your gut digests it into amino acids, the same building blocks you get from any protein food. There is no special route by which those pieces travel to your bone marrow and make blood.

Laboratory and animal studies have suggested that collagen peptides from donkey hide may nudge red blood cell production and immune signalling. These are early findings in cells and mice. They have not been confirmed in people, and results in mice often do not carry over.

One point matters for anyone taking E Jiao for "low blood". Iron deficiency is the most common cause of anaemia (low red blood cell count), and E Jiao contains very little iron. So it cannot correct an iron shortage the way an iron tablet or iron-rich food can.

In Chinese medicine terms, E Jiao is described as sweet, neutral and moistening, said to "nourish blood, stop bleeding, and moisten dryness". That is a traditional description of a pattern, not a measured biological action.

What forms does E Jiao come in?

E Jiao is sold in several forms:

Solid amber-brown blocks or flakes, the traditional raw form, meant to be melted into hot water, hot rice wine or a finished herbal decoction (a strained herbal tea).

Granules or small pieces that dissolve in hot liquid.

Gu Yuan Gao, a soft cake or paste that blends E Jiao with rock sugar, sesame, walnut and rice wine, sliced and eaten by the piece.

Read-to-drink tonic vials and instant sachets.

Capsules and tablets of powdered E Jiao.

Quality varies widely. Counterfeits made from cattle or pig hide, and in some reported cases from tanned leather scraps that can carry chromium, have been found in the market. Buy only from a licensed pharmacy or a supplier who can show batch testing.

Where it comes from:

E Jiao is one of the oldest named remedies in Chinese medicine. It appears in the Shen Nong Ben Cao Jing, a herbal text compiled around the first to second century CE, where it is placed in the top grade of medicines.

The name comes from Dong'e County in Shandong province, whose well water was said to give the best glue. It became a court tonic and remains one of the most expensive and most heavily marketed single substances in Chinese medicine.

It is a fixed part of classical formulas such as Jiao Ai Tang, used for bleeding in pregnancy, and Huang Lian E Jiao Tang, used for restlessness and insomnia.

What does E Jiao help with?

• Tiredness and pallor described in Chinese medicine as blood deficiency: This is E Jiao's main traditional use and it is a strong one within its tradition. Practitioners give it for a pale face, dizziness on standing, palpitations and general exhaustion. There are no good human trials showing E Jiao improves these symptoms better than a dummy treatment. Tiredness with pallor can mean iron deficiency, thyroid problems, bleeding in the gut or other treatable conditions. Get a blood test before you treat yourself.
• Heavy or prolonged menstrual bleeding: Traditional use is long-standing. E Jiao is described as helping to stop bleeding and rebuild blood afterwards, and it appears in classical formulas for exactly this. Modern proof is missing. There is no reliable trial showing it reduces menstrual blood loss. Heavy periods deserve a medical assessment, because fibroids, polyps, clotting problems and thyroid disease all cause them and all have specific treatments.
• Recovery after childbirth or blood loss: Traditionally given during the postpartum month to help a woman "rebuild blood". It is a widespread custom in China rather than a tested treatment. No human trial supports it. If you are bleeding heavily, feel faint, or your heart is racing after childbirth, that is a medical emergency and not something to manage with a tonic.
• Dry cough with little phlegm: Chinese medicine calls E Jiao moistening and uses it for a dry, tickly cough, especially in autumn or after a fever has burned out. Evidence here is traditional only. There are no trials in people. A cough lasting more than three weeks, or one with blood in it, needs a doctor.
• Low blood counts during chemotherapy: This is the most active area of modern interest. Some small Chinese studies and animal work suggest donkey-hide gelatin may support red and white cell counts during chemotherapy. The human studies we could find are small, poorly controlled and mostly published outside international journals, so they cannot support a firm claim. Never add E Jiao during cancer treatment without telling your oncologist (cancer doctor) first.
• Dry skin and brittle hair or nails: A modern marketing use rather than a classical one, resting on the fact that E Jiao is collagen. Collagen supplements in general have mixed and modest trial results for skin, and none of that work used E Jiao specifically. Treat beauty claims for E Jiao as unproven.
• Restless sleep in Chinese medicine patterns: E Jiao appears in the classical formula Huang Lian E Jiao Tang for insomnia with irritability and a dry mouth. That is a use within a multi-herb formula prescribed for a specific pattern, not evidence that E Jiao alone helps sleep. No trials test it on its own for insomnia.

Which foods are rich in E Jiao?

1. Nothing in an ordinary diet contains E Jiao: it is made only from donkey hide
2. Bone broth and pork skin dishes: these give similar collagen protein, though they are not the same product
3. Sesame seeds and walnuts: not sources of E Jiao, but the usual companions in E Jiao cakes

Practical Tips:

If you want the protein building blocks rather than the tradition, everyday collagen-rich foods supply the same amino acids far more cheaply.

What are the side effects of E Jiao?

• Bloating and a heavy, full feeling after eating
• Poor appetite
• Nausea
• Loose stools or, in some people, constipation
• Belching or reflux (stomach acid coming back up)
• A greasy or coated feeling in the mouth
• Allergic reaction, including rash or itching, in people sensitive to gelatin
• Blood sugar rises from sugar-sweetened cakes and tonic drinks
• Effects from alcohol in wine-processed cakes and tonics

Good to know:

Most side effects are digestive, mild and stop when you stop taking it.

Stomach upset is the common problem, and it is more likely if your digestion is already weak or you are taking a large dose. Chinese medicine has a name for this and warns against giving E Jiao to people with poor appetite, loose stools or a thickly coated tongue.

The more serious risk is not the substance itself but the product. Fake and adulterated E Jiao has been reported, including material made from tanned leather waste that can carry chromium, a metal that is harmful to the kidneys. Buying from a licensed pharmacy or a supplier with batch testing matters more here than with most herbs.

How much E Jiao should you take?

• Recommended daily: Traditional practice, not trial evidence, sets these amounts. There is no dose proven to produce a health effect. Raw blocks or granules: about 3 to 9 grams a day, melted into hot water, hot rice wine or a finished herbal decoction (a strained herbal tea). It is added at the end and not boiled, because boiling ruins the texture. Gu Yuan Gao cake: usually one or two slices a day, around 10 to 20 grams, as printed on the pack. Capsules and tonic drinks: follow the label, because the amount of actual E Jiao per dose varies a lot between brands. Start at the low end. E Jiao is rich and heavy, and larger amounts commonly cause bloating and a poor appetite.
• Best time of day: Usually once or twice a day, in the morning and early evening. Many practitioners advise the morning dose on an emptier stomach, but if it makes you feel queasy, move it to after a meal.
• With or without food: Either. Traditionally taken away from food for better absorption, but it is heavy and cloying, so take it with or just after food if it upsets your stomach. Avoid taking it at the same time as cold or raw food, according to traditional advice.
• Time to effect: Traditional sources describe changes over two to four weeks of daily use. Nothing works overnight, and no trial has measured how fast, or whether, any effect appears.
• How long to take it: Traditionally it is taken as a course of four to eight weeks, often through the colder months. Reassess after about four weeks. If nothing has changed, stop and get the underlying cause checked rather than continuing. Stop sooner if you get bloating, loose stools, nausea or a heavy, greasy feeling in your stomach.