Review for 10.1186/s12876-020-01220-3 (2020)

Reviewer ’s report  
 
Title: Effectiveness of concomitant use of green tea and polyethyl ene glycol in bowel 
preparation for colonoscopy: A randomized control led study  
 
Version: 0 Date: 16 Apr 2019  
 
Reviewer: Lawrence  Hookey  
 
Reviewer's report:  
This is a study comparing two bowel cleansing regimens, the control group receiving 2L peg 
with 1 litre of clear fluids, and the intervention group received 2L PEG with 1 litre o f green tea.  
All preparations were administered as same say preps.  
 
The green tea group had similar bowel cleansing but better tolerance.  
 
Comments:  
1. Overall the manuscript requires further editing for smoothness of language.  
2. I would eliminate casu al language such as "nowadays" - in abstract, and "tastes awful" in 
the introduction  
3. Why was the study retrospectively registered in a clinical trials database?  
4. Although the implementation appears well done, we need more information about the 
rational e behind the methodology - Was a power calculation performed? Why was a sample size 
of 120 chosen? What was the primary outcome?  
5. P values should not be presented as 0.000, they should be less than a number, such as 
&lt;0.001.  
6. The overall quality of c leansing in both groups seems less than one would expect, with 
only 27 per cent having a score of excellent or good, could the authors expand on why this may 
be?  
7. Who administered the questionnaire, with one of the main outcomes being patient 
tolerance,  an unbiased and blinded recorder is mandatory or the results could be heavily skewed.  
 
 
 
Are the methods appropriate and well described?  
If not, please specif y what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the  data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manus cript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, pleas e speci fy what aspects require further 
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from an  
organisation that may in any way gain or lose financially from the publi cation of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation t hat may in any way gain or lose 
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you curr ently applying for any patents  relating to the content of the 
manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds  or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any  other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have  no competing interests' 
below. If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests.  
 
I agree to the open peer review policy of the journal. I understan d that my name will be included 
on my report to the authors and, if the manuscript is accepted for publication, my named repo rt 
including any attachments I upload will be posted on the website  along with the authors' 
responses. I agree for my report to be made available under an Open Access Creative Commons  
CC-BY license ( http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments 
which I do not wish to be included in my named report can be in cluded as confidential comments 
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal