Condition category
Infections and Infestations
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
The common cold is a mild viral infection of the nose, throat, sinuses and upper airways. The aim of this study is to find out whether ResistAid™ (arabinogalactan), a sugar derived from larch trees, helps to decrease the incidence of the common cold by boosting the immune system.

Who can participate?
Healthy men and women aged 18-70 who have had at least three common cold infections within the last 6 months

What does the study involve?
Participants are randomly allocated to consume a sachet of ResistAid™ or placebo (dummy drug) daily with breakfast over a course of 12 weeks. Participants attend three visits: at the start of the study, after 6 weeks and at the end after 12 weeks. Additionally, if a cold occurs, there are two extra visits at the start and on the fifth day of the cold. Participants recorded their cold symptoms in a diary. The number, severity and duration of colds and side effects are assessed in both groups.

What are the possible benefits and risks of participating?
Participants may benefit from a reduced incidence of common cold, and there are no risks expected.

Where is the study run from?
Analyze & Realize AG (Germany)

When is the study starting and how long is it expected to run for?
October 2010 to May 2011

Who is funding the study?
Lonza Ltd (Switzerland)

Who is the main contact?
Dr Linda Böhme

Trial website

Contact information



Primary contact

Dr Linda Böhme


Contact details

Analyze & Realize AG
Waldseeweg 6
+49 (0)30 4000 8152

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Double-blind, randomized, placebo-controlled clinical study to evaluate the immune-enhancing properties of a proprietary larch arabinogalactan (ResistAid™) by assessing the incidence of common cold


Study hypothesis

The incidence of common cold during the study period is expected to be decreased in the verum study arm compared to the placebo study arm.

Ethics approval

Charité (Universitaetsmedizin Berlin, Campus Charité Mitte), 12/10/2010, ref: EA1/208/10

Study design

Double-blind randomized placebo-controlled multi-centre clinical study

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details to request a patient information sheet


Immune function


ResistAid™ study arm compared to placebo study arm

Intake of one sachet (4.5g) daily with breakfast. A total of three basic visits were performed: Visit 1 at study start (=baseline), Control Visit after 6 weeks and Termination Visit after 12 weeks. Additionally, if a cold episode occurred, an Episode Visit was performed at start and on the 5th day of each episode. A cold episode was defined by having (any of) the following symptoms: headache, joint pain, sore throat, difficulty swallowing, hoarseness, coughing, watery nasal discharge, nasal congestion, cold related sleeping difficulties, and body temperature above 38°C. During an episode, the subjects recorded and assessed their cold symptoms in the subject diary, for a period of 14 days. The diaries were checked by the investigators at the second Episode Visit of each episode. At study end (Termination Visit), the investigators and the subjects assessed the global efficacy and tolerability of the investigational product. At the start and end of the study, subjects recorded their eating habits in a diet diary. Further, the safety laboratory parameters as well as special laboratory parameters (leukocyte differentiation) were assessed at baseline and end of study.

Intervention type



Not Applicable

Drug names

Larch arabinogalactan (ResistAid™)

Primary outcome measure

Number of cold episodes during the study period

Secondary outcome measures

1. Duration of cold episodes (based on subject diary)
2. Episode intensity assessed per change of the total sum score after 5 days compared to start of episode (first Episode Visit), based on case report form (CRF) and subject diary
3. Episode intensity at start of episode (sum score on Day 1 based on subject diary, i.e. at first Episode Visit based on CRF)
4. Global assessment of efficacy and tolerability
5. Assessment of adverse events
6. Assessment of laboratory parameters including leucocyte differentiation
7. Assessment of eating habits based on a 3-day-record

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Age 18 - 70 years (child-bearing females had to agree to use appropriate birth control methods)
2. Recurrent infections of upper airways (at least 3 episodes in half-year according to subject’s statement)
3. Written consent of the subject to study participation, subject understands the requirements and is willing to comply

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Acute infection of the upper airways
2. Chronic upper airways disease (e.g. chronic bronchitis or asthma)
3. Suspected influenza or swine flu
4. Body temperature above 38°C
5. Vaccination against influenza or swine flu within 21 days before study start
6. Serious organ or systemic diseases
7. Body mass index above 30
8. Clinically significant abnormal laboratory parameters (values outside of reference range)
9. Known sensitivity to the ingredients of the investigational product
10. Inborn or acquired immune deficiency disease (e.g. HIV infection)
11. Pregnancy and nursing
12. Use of following medication:
12.1. Immunosuppressive agents
12.2. Immunostimulating agents, e.g. Echinacea
12.3. Local oral and pharyngeal treatment
12.4. Antibiotics within 14 days before study start
13. Drugs, alcohol and medical abuse
14. Use of prebiotics and probiotics (e.g. yogurt, drinks, supplements)
15. Participation in another clinical study at or within 30 days before study start
16. Inability to comply with study requirements

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Analyze & Realize AG

Sponsor information


Lonza Ltd (Switzerland)

Sponsor details

Münchensteinerstrasse 38

Sponsor type




Funder type


Funder name

Lonza Ltd (Switzerland)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2013 results in

Publication citations

  1. Results

    Riede L, Grube B, Gruenwald J, Larch arabinogalactan effects on reducing incidence of upper respiratory infections., Curr Med Res Opin, 2013, 29, 3, 251-258, doi: 10.1185/03007995.2013.765837.

Additional files

Editorial Notes

05/10/2016: Plain English summary added.