What is Sang Piao Xiao?

Sang Piao Xiao is the dried egg case of the praying mantis. In Chinese medicine it is used for bedwetting in children, for passing urine often at night, and for some men's sexual complaints. It is nearly always used inside a herb formula, not on its own.

The name means "mulberry egg case". Egg cases laid on mulberry branches were counted as the best grade. Today it is sold as a whole dried case, as broken pieces, or as a powder.

Here is the short verdict. No human trials of this single herb have been published that we can point to. Long use in China is real, but long use on its own is not proof that a remedy works.

How does Sang Piao Xiao work?

The honest answer is that nobody has shown how it works in people.

In Chinese medicine theory it is said to hold the kidney and bladder firm, so that urine is kept in. That is a traditional idea, not a tested mechanism. It is also said to be warming, so it is matched to people who feel cold and tired.

Lab tests show the egg case holds protein, fat and minerals. A few animal and test-tube studies hint at effects on blood sugar and on cell damage. These are early findings and do not tell you what happens in a person.

What forms does Sang Piao Xiao come in?

Most often it is a whole dried egg case, boiled into a decoction (a tea made by simmering raw herbs). Herbalists usually steam it or dry-fry it first. That is the standard way it is made ready for use.

It also comes as granules, powder or pills inside ready-made formulas. The best known of these is Sang Piao Xiao San. It is rarely sold on its own in the West.

Where it comes from:

It appears in the Shen Nong Ben Cao Jing, a Chinese herb book from about 1,800 years ago. A doctor named Kou Zongshi wrote up the formula Sang Piao Xiao San in the 12th century.

The herb has stayed in steady use in China since then. Its main job has always been the same: bedwetting, frequent urination, and leaking of urine in older people.

What does Sang Piao Xiao help with?

• Bedwetting in children: This is the oldest and best known use. Chinese texts have recommended it for centuries, usually inside the formula Sang Piao Xiao San. We found no published human trial of the single herb for bedwetting. A child who wets the bed should be checked by a doctor first, since infection, diabetes and constipation can all cause it.
• Needing to pass urine often, especially at night: Traditionally used when the urine is clear and pale and the person feels cold and tired. There is no trial evidence we can cite for this use. Waking often to pass urine can be a sign of a bladder infection, an enlarged prostate (a gland near the bladder in men) or diabetes, so get it looked at.
• Leaking of urine in older adults: Chinese herbalists use it as one part of a warming formula for weak bladder control. No human trials support this. Proven options such as pelvic floor exercises and prescription bladder medicines have far better evidence.
• Semen loss during sleep or very quick ejaculation: Classical texts group these with weak bladder control and use the same herb. This rests on tradition alone. We found no human research testing it for these problems.
• Ongoing vaginal discharge: A secondary traditional use, again for a pattern seen as cold and weak rather than hot. There is no trial evidence. New or smelly discharge needs a doctor, because it may be an infection.

What are the side effects of Sang Piao Xiao?

• Allergic reaction, such as rash, itching or swelling
• Wheezing or a tight chest in people allergic to insects or shellfish
• Nausea or stomach upset
• Dry mouth
• Constipation
• Bad taste that some people find hard to swallow

Good to know:

Reports of harm are rare, but this is partly because so little has been recorded. The main real concern is allergy, since this is an insect product and insect protein can trigger the same reaction as shellfish or dust mites. Stop taking it if you get a rash, itching or any trouble breathing.

How much Sang Piao Xiao should you take?

• Recommended daily: No dose has been set by research. In Chinese practice, 5 to 10 grams of the dried egg case a day is simmered into a tea, usually with several other herbs. Children are given less, based on age and weight, and a qualified practitioner should set that amount.
• Best time of day: Usually in the morning and early evening. For bedwetting, the last dose is often given a few hours before bed rather than at bedtime, so fluid is not taken in late.
• With or without food: Take it between meals or shortly after food. If it upsets your stomach, take it with food.
• Time to effect: Unknown. Traditional practice expects some change within two to four weeks, but no study has measured this.
• How long to take it: It is normally taken for a few weeks inside a formula, not for years. If nothing has changed after four weeks, stop and get the problem checked. Anyone taking it for longer than this should be reviewed by the person who prescribed it.