What is Xing Su San?

Xing Su San is a Chinese herbal formula for a new, tight cough. It suits a cough with thin white phlegm that starts after cold, dry weather. Its English name is Apricot Kernel and Perilla Leaf Powder.

We count it as one drug in this library, though it is a blend of about ten herbs. A practitioner would pick it for a dry cough with a blocked or runny nose. A scratchy throat, a stuffy chest and mild chills fit the picture too.

Take it as a short course while those signs last. It is not a daily tonic.

On the evidence: the formula has held a firm place in Chinese medicine for more than two hundred years. But we found no published human trials of the whole formula. Long use is not proof that something works, and that caution covers every claim on this page.

How does Xing Su San work?

Honestly, no one has shown how this formula acts in the human body. What follows is traditional thinking plus hints from lab work. It is not proof of how the formula works.

In Chinese medicine, the formula is said to "scatter cold dryness". It is also said to move stuck lung qi downward, so phlegm loosens and the cough settles. That is a traditional model of the body, not measured chemistry.

In modern terms, some of the herbs show effects in test tubes and animals. Perilla leaf and tangerine peel oils relax airway muscle. Platycodon root thins mucus, and licorice soothes sore tissue.

These findings are early. They do not tell you what the finished brew does in a person with a cough.

What forms does Xing Su San come in?

The old form is a coarse powder, simmered in water with fresh ginger and jujube. You then strain it and drink it warm. Many clinics now supply granules or a dried extract that you stir into hot water.

You may also meet it as pills or capsules of strong extract. Strength varies a lot from maker to maker. So the dose on the label counts for more than any general figure.

Buy only from a supplier who states two things. First, that the pinellia is processed, which means prepared to cut its throat-burning toxicity. Second, that the apricot kernel is the prepared, heat-treated kind.

Where it comes from:

The formula comes from Wen Bing Tiao Bian (Systematic Differentiation of Warm Diseases). Wu Ju-tong wrote it, and it came out in 1798. He made it for what that text calls cool dryness attacking the lung in autumn.

It has stayed in use in Chinese medicine ever since. Standard modern formula textbooks still teach it. It is a staple of one tradition, not a remedy shared across many.

What does Xing Su San help with?

• Recent dry or tight cough after cold, dry weather: This is the formula's core traditional use, and it is where practitioners use it most. We found no human trials testing it for cough, so its benefit here rests on tradition and clinical habit alone. A cough lasting more than three weeks needs a doctor, not a herbal course.
• Common cold with blocked nose and scratchy throat: Tradition uses it in the first days of a cold when you feel chilly and your nose runs clear. There is no trial evidence that it shortens a cold or eases its symptoms. Nothing here treats influenza, COVID-19 or a chest infection.
• Chest tightness with thin white phlegm: The formula is aimed at loose, watery phlegm rather than thick yellow or green phlegm, which tradition treats differently. Laboratory work suggests some of the herbs may loosen mucus, but that has not been tested in people taking this mixture. New chest tightness with breathlessness is a reason to seek care, not to self-treat.
• Early-stage seasonal cough in Chinese medicine practice: In practice it is prescribed for a few days at the start of symptoms and then stopped or changed. Its standing is traditional; the evidence grade for it is insufficient. Do not use it as a long-term cough remedy.

Which foods are rich in Xing Su San?

1. Perilla leaf (shiso): the same leaf is eaten in Japanese and Korean cooking
2. Fresh ginger: a kitchen spice and one of the formula's finishing herbs
3. Jujube dates: eaten as a dried fruit across East Asia
4. Dried tangerine peel: used in Chinese cooking and stocks

Practical Tips:

Eating these foods is not the same as taking the formula, and the food amounts are far smaller.

What are the side effects of Xing Su San?

• Nausea or an upset stomach
• Dry mouth or throat irritation
• Mild drowsiness
• Loose stools
• Skin rash or itching (an allergic reaction)
• Swollen ankles and raised blood pressure with longer use, from the licorice
• Low potassium with longer use, which can cause muscle weakness and cramps
• Palpitations (a racing or thumping heartbeat), linked to the bitter orange peel
• Headache, dizziness or confusion, which can be early signs of cyanide poisoning from too much apricot kernel

Good to know:

At label doses and for a few days, most people get either nothing or mild stomach upset. The serious effects listed above are uncommon and are tied to taking too much, or taking it for too long.

Two ingredients set the real limits. Licorice can raise blood pressure and drop potassium over weeks, and bitter apricot kernel can release cyanide, a poison, if the dose is exceeded or raw kernels are used.

Stop the formula and get medical advice if you develop swollen ankles, muscle weakness, a racing heartbeat, confusion or blue-tinged lips.

How much Xing Su San should you take?

• Recommended daily: There is no dose established by research. The figures below are traditional practice, and the label on your product overrides them. A common traditional decoction uses roughly 6 to 9 grams each of the main herbs, simmered and split into two or three warm drinks a day. Concentrated granules are usually 3 to 9 grams of granule a day, divided into two or three doses. Never exceed the label dose. Bitter apricot kernel and licorice both become harmful in larger amounts, so "more" is not safer or stronger.
• Best time of day: Traditionally taken warm, two or three times a day, spread across the day. A dose in the evening is usual when the cough disturbs sleep.
• With or without food: Usually taken between meals, warm. If it upsets your stomach, take it shortly after food instead.
• Time to effect: Traditional practice expects some easing within one to three days. No trial has measured this, so treat it as expectation rather than fact.
• How long to take it: Treat it as a short course. Most traditional use runs three to seven days, only while the cough and cold symptoms are present. Stop and see a doctor if you are no better after a week. Because of the licorice content, courses beyond two weeks are not advised without supervision.