ISO 19842

Traditional Chinese medicine — Dioscorea opposita rhizome

This document specifies the quality and safety requirements and test methods of Dioscorea opposita rhizome, which is the dried from rhizome of Dioscorea opposita Thunb. This document is applicable to Dioscorea opposita rhizome that are sold and used as natural medicines in international trade, including Chinese Materia Medica (whole medicinal material) and decoction pieces derived from this plant.

Médecine traditionnelle Chinoise — Rhizome de Dioscorea opposita

General Information

• Status: Not Published
• ICS: 11.120.10 - Medicaments
• Technical Committee: ISO/TC 249 - Traditional Chinese medicine
• Drafting Committee: ISO/TC 249 - Traditional Chinese medicine
• Current Stage: 6000 - International Standard under publication
• Start Date: 08-Apr-2025
• Completion Date: 26-Apr-2025

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/FDIS 19842
ISO/TC 249
Traditional Chinese medicine —
Secretariat: SAC
Dioscorea opposita rhizome
Voting begins on:
2025-02-10
Voting terminates on:
2025-04-07
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/FDIS 19842:2025(en) © ISO 2025

FINAL DRAFT
ISO/FDIS 19842:2025(en)
International
Standard
ISO/FDIS 19842
ISO/TC 249
Traditional Chinese medicine —
Secretariat: SAC
Dioscorea opposita rhizome
Voting begins on:
Voting terminates on:
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/FDIS 19842:2025(en) © ISO 2025

ii
ISO/FDIS 19842:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Descriptions . 1
5 Quality and safety requirements and recommendations . 2
5.1 General characteristics .2
5.2 Morphological features .2
5.3 Microscopic characteristics .2
5.4 Moisture .3
5.5 Total ash .3
5.6 Water-soluble extractives .3
5.7 Thin-layer chromatogram (TLC) identification .3
5.8 Heavy metals .3
5.9 Pesticide residues .3
5.10 Sulfur dioxide . .4
6 Sampling . 4
7 Test methods . 4
7.1 Macroscopic identification .4
7.2 Microscopic identification .4
7.3 Determination of moisture .4
7.4 Determination of total ash .4
7.5 Determination of water-soluble extractives .4
7.6 Thin-layer chromatogram (TLC) identification .4
7.7 Determination of heavy metals .4
7.8 Determination of pesticide residues .4
7.9 Determination of sulfur dioxide .4
8 Test report . 4
9 Packaging, storage and transportation . 5
10 Marking and labelling . 5
Annex A (informative) Thin-layer chromatogram (TLC) identification . 6
Annex B (informative) Referenced values of national and regional limits for Dioscorea opposita
rhizome . 8
Bibliography .10

iii
ISO/FDIS 19842:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 249, Traditional Chinese medicine.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO/FDIS 19842:2025(en)
Introduction
Dioscorea opposita rhizome is the dried rhizome of Dioscorea opposita Thunb. It has a long history of
application as a traditional Chinese herb in China, the Republic of Korea, Japan, etc. It is widely used clinically
for its efficacy in nourishing the spleen and stomach, generating body fluid and benefiting the lungs, and
tonifying the kidneys and acting as an astringent essence. Dioscorea opposita rhizome is mostly processed
into Dioscorea opposita rhizome decoction pieces, bran-fried Dioscorea opposita rhizome and other products
circulating in the market. Dioscorea opposita rhizome has a long history of cultivation and is grown all over
the world. In 2020, the global Dioscorea opposita rhizome cultivation area is about 9,205 million hectares and
Dioscorea opposita rhizome production is about 76,031 million tonnes, both of which are on a growing trend.
To date, Dioscorea opposita rhizome has been widely recorded in established pharmacopoeias such
as the Chinese Pharmacopoeia, Korean Pharmacopoeia, Japanese Pharmacopoeia, and the European
Pharmacopoeia. But different quality requirements in different countries and regions, different packaging,
transportation and storage conditions can affect the quality of Dioscorea opposita rhizome. Meanwhile,
Dioscorea opposita rhizome occupies the No. 65 place on the priority list of ISO/TR 23975. Therefore, it is
urgent and necessary to establish a unified international standard for Dioscorea opposita rhizome to ensure
its quality and safety.
As national implementation can differ, national standards bodies are invited to modify the values given in
5.4 and 5.5 in their national standards. Examples of national and regional values are given in Annex B.

v
FINAL DRAFT International Standard ISO/FDIS 19842:2025(en)
Traditional Chinese medicine — Dioscorea opposita rhizome
1 Scope
This document specifies the quality and safety requirements and test methods of Dioscorea opposita rhizome
(dried rhizome of Dioscorea opposita Thunb.).
It is applicable to Dioscorea opposita rhizomes that are sold and used as natural medicines in international trade,
including Chinese materia medica (whole medicinal material) and decoction pieces derived from this plant.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 18664, Traditional Chinese Medicine — Determination of heavy metals in herbal medicines used in
Traditional Chinese Medicine
IS
...

ISO/FDIS 19842:2025(en)
ISO/TC 249/ WG 1
Secretariat: SAC
Date: 2024-12-232025-01-27
Traditional Chinese medicine – — Dioscorea opposita rhizome
FDIS stage
ISO #####-#:####(X/FDIS 19842:2025(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2022 – All rights reserved

ISO/FDIS 19842:2025(en)
Contents Page
Foreword . Error! Bookmark not defined.
Introduction . Error! Bookmark not defined.
1 Scope . Error! Bookmark not defined.
2 Normative references . Error! Bookmark not defined.
3 Terms and definitions . Error! Bookmark not defined.
4 Descriptions . Error! Bookmark not defined.
5 Quality and safety requirements and recommendations . Error! Bookmark not defined.
5.1 General characteristics . Error! Bookmark not defined.
5.2 Morphological features . Error! Bookmark not defined.
5.3 Microscopic characteristics . Error! Bookmark not defined.
5.4 Moisture . Error! Bookmark not defined.
5.5 Total ash . Error! Bookmark not defined.
5.6 Water-soluble extractives . Error! Bookmark not defined.
5.7 Thin-layer chromatogram (TLC) identification . Error! Bookmark not defined.
5.8 Heavy metals . Error! Bookmark not defined.
5.9 Pesticide residues . Error! Bookmark not defined.
5.10 Sulfur dioxide . Error! Bookmark not defined.
6 Sampling . Error! Bookmark not defined.
7 Test methods . Error! Bookmark not defined.
7.1 Macroscopic identification . Error! Bookmark not defined.
7.2 Microscopic identification . Error! Bookmark not defined.
7.3 Determination of moisture . Error! Bookmark not defined.
7.4 Determination of total ash . Error! Bookmark not defined.
7.5 Determination of water-soluble extractives . Error! Bookmark not defined.
7.6 Thin-layer chromatogram (TLC) identification . Error! Bookmark not defined.
7.7 Determination of heavy metals . Error! Bookmark not defined.
7.8 Determination of pesticide residues . Error! Bookmark not defined.
7.9 Determination of sulfur dioxide . Error! Bookmark not defined.
8 Test report . Error! Bookmark not defined.
9 Packaging, storage and transportation . Error! Bookmark not defined.
10 Marking and labelling . Error! Bookmark not defined.
(informative) Thin-layer chromatogram (TLC) identification . Error! Bookmark not defined.
(informative) Referenced values of national and regional limits for Dioscorea opposita
rhizome . Error! Bookmark not defined.
Bibliography . Error! Bookmark not defined.

iii
ISO #####-#:####(X/FDIS 19842:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 249, Traditional Chinese medicine.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv © ISO 2022 – All rights reserved

ISO/FDIS 19842:2025(en)
Introduction
Dioscorea opposita rhizome is the dried rhizome of Dioscorea opposita Thunb. It has a long history of
application as a traditional Chinese herb in China, the Republic of Korea, Japan, etc. It is widely used clinically
for its efficacy in nourishing the spleen and stomach, generating body fluid and benefiting the lungs, and
tonifying the kidneys and acting as an astringent essence. Dioscorea opposita rhizome is mostly processed into
Dioscorea opposita rhizome decoction pieces, bran-fried Dioscorea opposita rhizome and other products
circulating in the market. Dioscorea opposita rhizome has a long history of cultivation and is grown all over
the world. In 2020, the global Dioscorea opposita rhizome cultivation area is about 9,205 million hectares and
Dioscorea opposita rhizome production is about 76,031 million tonnes, both of which are on a growing trend.
To date, Dioscorea opposita rhizome has been widely recorded in the established pharmacopoeias such as the
Chinese Pharmacopoeia, Korean Pharmacopoeia, Japanese Pharmacopoeia, and the European Pharmacopoeia.
But different quality requirements in different countries and regions, different packaging, transportation and
storage conditions can affect the quality of Dioscorea opposita rhizome. Meanwhile, Dioscorea opposita
rhizome occupies the No. 65 place on the priority list of ISO/TR 23975. Therefore, it is urgent and necessary
to establish ana unified international standard for Dioscorea opposita rhizome to ensure its quality and safety.
As national implementation can differ, national standards bodies are invited to modify the values given in
5.45.4 and 5.55.5 in their national standards. Examples of national and regional values are given in
Annex BAnnex B.
v
FINAL DRAFT International Standard ISO/FDIS 19842:2025(en)

Traditional Chinese medicine – — Dioscorea opposita rhizome
1 Scope
This document specifies the quality and safety requirements and test methods of Dioscorea opposita rhizome
(dried rhizome of Dioscorea opposita Thunb.).
It is applicable to Dioscorea opposita rhizomes that are sold and used as natural medicines in international
trade, including Chinese materia medica (whole medicinal material) and decoction pieces derived from this
plant.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 18664, Traditional Chinese Medicine — Determination of heavy metals in herbal medicines used in
Traditional Chinese Medicine
ISO/TS 21310, Traditional Chinese medicine — Microscopic examination of medicinal herbs
ISO 21371, Traditional Chinese medicine — Labelling requirements of products intended for oral or topical use
ISO 22217, Traditional Chinese medicine —Storage requirements for raw materials and decoction pieces
ISO 22258, Traditional Chinese medicine — Determination of pesticide residues in herbal medicines used in
Traditional Chinese Medicinenatural products by gas chromatography
ISO 22590, Traditional Chinese medicine — Determination of sulfur dioxide in natural products by titration
ISO 23723, Traditional Chinese medicine — General requirements for herbal raw material and materia medica
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
3.1 3.1
Dioscorea opposita rhizome
dried rhizome of Dioscorea opposita Thunb. (syn. Dioscorea batatas Decne. or Dioscorea polystachya Turcz.) in
the family of Dioscoreaceae.
ISO #####-#:####(X/FDIS 19842:2025(en)
4 Descriptions
The features of Dioscorea opposita Thunb. plant in the family of Dioscoreaceae are shown in Figure 1Figure 1.

Key
1 leaf
2 rhizome
3 decoction pieces of Dioscoreadioscorea opposita rhizome
Figure 1 — Features of Dioscorea opposita Thunb. plant
2 © ISO 2022 – All rights reserved

ISO/FDIS 19842:2025(en)
5 Quality and safety requirements and recommendations
5.1 General characteristics
The following requirements shall be met before sampling.
a) a) Dioscorea opposita rhizome shall be clean and free from leaves and foreign matter.
b) b) The presence of living insects, mouldy branch and external contaminants which are visible to the
naked eye shall not be permitted.
5.2 Morphological features
This raw materia medica is slightly cylindrical, curved and slightly flat, 15 cm to 30 cm long, 1,5 cm to 6 cm in
diameter. It has yellowish white or yellowish surface, with longitudinal grooves, longitudinal wrinkles and
bearded root traces, occasionally light brown outer skin residue. The body is heavy, solid, not easy to break;
the section is white, powdery. The smell is slight; the taste is light and slightly acid. It is sticky when chewed.
5.3 Microscopic characteristics
The microscopic characteristics of Dioscorea opposita rhizome are shown in Figure 2. The powder (particle
diameter < 250 μm) is whitish or yellowish-white with the following characteristics:
a) a) starch granules are flat-oval, triangular-oval, round-like or rectangular, 8 μm to 35 μm in diameter,
umbilical dotted, herringbone, cruciform or short sutured, with visible laminae;
b) b) fragments of parenchyma consist of thin-walled polyhedral or ovoid cells;
c) c) reticulate or pitted vessels are 12 μm to 48 μm in diameter;
d) d) calcium oxalate needle crystal bundles exist freely or in mucous cells, about 240 μm long, with needle
crystal 2 μm to 5 μm thick.
ISO #####-#:####(X/FDIS 19842:2025(en)

Key
1 starch granules
2 thin-walled cells
3 reticulate or pitted vessels
4 calcium oxalate needle crystal bundles
Figure 2 — Microscopic characteristics of Dioscorea opposita rhizome
5.4 Moisture
The mass fraction of moisture should not be more than 16,0 %.
4 © ISO 2022 – All rights reserved
...