Yi Tang (Barley Malt Sugar, Maltose)

Chinese Herb Actions

Chinese Herb Dosage

• What is the typical dosage of Yi Tang?

  Roughly 15–30 g in formulas, up to 30–60 g when used as a standalone remedy. The site’s own formula data records Yi Tang at 18–30 g as the chief herb in both Xiao Jian Zhong Tang and Da Jian Zhong Tang, consistent with the higher standalone range seen in general materia medica sources. Because it is a syrup/paste rather than a dried herb, preparation is distinctive.

  • Not decocted with the other herbs. Yi Tang is dissolved into the hot, strained decoction after the other ingredients have been cooked and strained — the same "melt-in" method used for gelatin-type substances like E Jiao, but for a sugar rather than a gelatin.
  • Other forms. General references also describe it smashed into powder after melting or stir-baking, or made into pills and paste.

  Source: Sacred Lotus formula data (composition: Xiao Jian Zhong Tang, Da Jian Zhong Tang, 18–30 g); multiple online sources (30–60 g standalone dose; preparation). Reference only — not a prescription.

Chinese Herb Contraindications & Cautions

• Are there cautions for Yi Tang?

  Yi Tang is a concentrated sugar, so it is contraindicated wherever dampness, heat, or fullness are already present. Materia medica sources consistently list damp-heat accumulation (especially with nausea/vomiting), middle-burner fullness or distention, and phlegm-heat cough with copious sputum as contraindications — its cloying sweetness can aggravate all three.

  • Blood sugar (reference note) — because Yi Tang is essentially maltose, a fast-acting sugar, it is generally avoided or reduced in patients with diabetes or blood-sugar sensitivity; when removed from a formula for this reason, the remaining herbs (e.g., Bai Shao and Gan Cao in Xiao Jian Zhong Tang) retain the core tension-relaxing action, though with reduced nourishing power.
  • Children/overuse (reference note) — general references caution that excess intake of malt sugar in children can foster dampness and promote dental caries; some classical sources also link overindulgence in sweets to intestinal parasitism, which reflects traditional theory rather than a modern clinical finding.

  Source: multiple online sources (contraindications); glycemic research (below). Reference disclosures, not usage instructions.

Chinese Herb Toxicity & Overdose

• Low. Yi Tang is classified as non-toxic in the traditional materia medica — it is a food-grade product (malted grain sugar) with a long dietary history and no significant toxicity reported at customary doses. The main real-world concern is not intrinsic toxicity but its sugar content: as a fast-acting, concentrated carbohydrate it can raise blood glucose and, with habitual overuse (especially in children), contribute to dental caries and internal damp-heat.

  Source: materia medica consensus; maltose glycemic/dental research (below). Reference note, not a safety guarantee.

Herb-Drug Interactions

• No specific herb–drug interactions are documented for Yi Tang in the TCM literature. The practical consideration is glycemic, not pharmacokinetic: because maltose is rapidly hydrolyzed to glucose and produces a strong postprandial glucose response, patients on glucose-lowering medication or with diabetes should be aware that Yi Tang (and formulas containing it, such as Xiao Jian Zhong Tang) can meaningfully raise blood sugar. (Precautionary, based on maltose’s known glycemic behavior — not a demonstrated drug interaction.)

Western / Biomedical Research

Chinese Herb Clinical Studies & Research

Provided as research context — a summary of published biomedical study, not a therapeutic or medical claim.

• Is there modern research on Yi Tang (Saccharum Granorum) or its main constituent, maltose?

  Yi Tang itself has not been studied as a standardized extract, but its constituent sugar, maltose, and related barley-malt products have supporting research. Chemically, Yi Tang is essentially maltose (a disaccharide of two glucose units) produced by enzymatic hydrolysis of grain starch during malting.

  • Glycemic response (animal) — a classic metabolic study found that rats fed high-maltose or high-sucrose diets developed impaired glucose tolerance and higher glucose-induced insulin release compared to an isocaloric starch-rich diet, supporting the traditional caution around Yi Tang and blood sugar.
  • Dental effects (human, crossover) — a double-blind crossover study had adults follow sucrose-rich and maltose-rich diets in turn and compared dental plaque; maltose produced a similar acidic plaque-pH response to sucrose but a different plaque polysaccharide composition, indicating maltose is not a "safer" sugar for teeth even though its plaque chemistry differs somewhat from sucrose.
  • Barley-derived laxative effect (animal, adjacent product) — a 2019 study found that a fermented barley extract (a different, enzyme-processed barley product, not Yi Tang/maltose itself) improved stool water content and intestinal motility in a loperamide-induced constipation rat model. It is included here only as adjacent context on barley-derived carbohydrate products and should not be read as evidence for Yi Tang specifically.

  Note: The fermented-barley-extract laxative study (PMID 31226979) concerns a distinct, fermented barley preparation, not maltose/malt sugar itself; it is cited only as related context on barley-derived carbohydrates and kept clearly separated from the maltose-specific findings above.

  Sources: PMID 669563 (Laube et al., Horm Metab Res 1978, high-maltose/sucrose feeding and glucose tolerance in rats); PMID 6957174 (Skinner et al., Arch Oral Biol 1982, maltose vs. sucrose and human dental plaque); PMID 31226979, DOI 10.1186/s12906-019-2557-x (fermented barley extract and loperamide-induced constipation in rats). Research context on maltose/barley-derived carbohydrates, not a therapeutic claim for Yi Tang.

Chinese Herb Notes

• How is Yi Tang used in formulas, and how does it differ from other Spleen-qi tonics?

  Yi Tang is unusual among the qi tonics for its sweet, tension-relaxing action — where herbs like Ren Shen, Huang Qi, and Bai Zhu build qi through direct tonification, Yi Tang’s combination of sweetness and warmth specifically relaxes cramping and spasm in the middle jiao, an action it shares mainly with Bai Shao and Gan Cao.

  • Xiao Jian Zhong Tang (Minor Construct the Middle Decoction) — Yi Tang is the chief herb, paired with Gui Zhi and Sheng Jiang to warm, and Bai Shao and Zhi Gan Cao to relax tension; together they treat middle-yang deficiency cold with intermittent, spasmodic abdominal pain better with warmth and pressure. Per the site’s formula data, Yi Tang is dissolved into the strained decoction rather than decocted with the rest.
  • Da Jian Zhong Tang (Major Construct the Middle Decoction) — Yi Tang again appears at 18–30 g, here supporting a stronger warming formula (with Chuan Jiao and Gan Jiang/Ren Shen) for more severe yang-deficiency cold with upward-surging abdominal pain.
  • Combination pairs commonly described in materia medica references: Yi Tang with Gui Zhi to warm the middle and relieve cramping, and Yi Tang with Bai Shao for Liver-Spleen disharmony pain.

  Source: Sacred Lotus formula data (formulas/the composition record: xiao-jian-zhong-tang, da-jian-zhong-tang); multiple online sources (differentiation and combinations). Traditional formula context, not treatment advice.