Prospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Pharmacol Ther. Jul 5, 2021; 12(4): 79-89
Published online Jul 5, 2021. doi: 10.4292/wjgpt.v12.i4.79
Castor oil as booster for colon capsule endoscopy preparation reduction: A prospective pilot study and patient questionnaire
Kota Takashima, Yoriaki Komeda, Toshiharu Sakurai, Sho Masaki, Tomoyuki Nagai, Shigenaga Matsui, Satoru Hagiwara, Mamoru Takenaka, Naoshi Nishida, Hiroshi Kashida, Konosuke Nakaji, Tomohiro Watanabe, Masatoshi Kudo
Kota Takashima, Yoriaki Komeda, Toshiharu Sakurai, Sho Masaki, Tomoyuki Nagai, Shigenaga Matsui, Satoru Hagiwara, Mamoru Takenaka, Naoshi Nishida, Hiroshi Kashida, Tomohiro Watanabe, Masatoshi Kudo, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka 589-8511, Japan
Konosuke Nakaji, Division of Gastroenterology, Department of Internal Medicine, Endoscopy Center, Aishinkai Nakae Hospital, Wakayama-Shi 640-8461, Japan
Author contributions: Komeda Y contributed conceptualization, methodology, and formal analysis; Takashima K and Komeda Y contributed investigation, and wrote original draft; Watanabe T and Kudo M reviewed and edited the manuscript; Sakurai T, Masaki S, Nagai T, Matsui S, Takenaka M, Nishida N, Kashida H, and Nakaji K contributed data collection; Hagiwara S contributed statistical analysis; all authors have read and agreed to the published version of the manuscript.
Institutional review board statement: This study was approved by the Institutional Review Board of Kindai University Hospital (29-087) and the procedures were in accordance with the Declaration of Helsinki.
Clinical trial registration statement: The clinical trial is registered with University Hospital Medical Information Network, using identifier UMIN000028694. Details can be found at
Informed consent statement: All study participants, or their legal guardian, provided written consent prior to study enrollment.
Conflict-of-interest statement: The authors of this manuscript have no conflicts of interest to disclose.
Data sharing statement: No additional data are available.
CONSORT 2010 statement: The authors have read the CONSORT 2010 Statement, and the manuscript was prepared and revised according to the CONSORT 2010 Statement.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Yoriaki Komeda, MD, PhD, Senior Lecturer, Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, 377-2, Ohno-higashi, Osaka 589-8511, Japan.
Received: February 2, 2021
Peer-review started: February 2, 2021
First decision: February 24, 2021
Revised: March 22, 2021
Accepted: May 20, 2021
Article in press: May 20, 2021
Published online: July 5, 2021
Research background

Colon capsule endoscopy (CCE) is a usefulness imaging modality because it can be performed non-invasively. However, there is one major limitation of CCE, as bowel preparations for CCE require a larger volume of laxative than that used in conventional colonoscopy because of the need for capsule excretion completion. Therefore, the development of a new bowel preparation method with comparable liquid volume to colonoscopy is necessary to increase patients’ CCE tolerability.

Research motivation

Castor oil could have the potential to accelerate the capsule excretion through the colon and reduce the volume of the liquid laxative.

Research objectives

In this study, we attempted to clarify the effectiveness and tolerability of our modified regimen, which uses castor oil as a booster.

Research methods

Twenty patients suspected of colorectal diseases were enrolled in this prospective cohort study. We used modified CCE regimen using castor oil as a booster. The capsule excretion rate within the battery life, bowel cleansing level in different segments of the colorectum, and detection rates of colorectal lesions were evaluated. In this study, we asked the patients to complete a questionnaire to assess the CCE tolerability.

Research results

Seventeen patients (85%) successfully followed our castor oil–based regimen, whereas three patients (15%) were unable to ingest castor oil because of its taste and failed to expel the capsule within the duration of battery life. The mean large bowel transit time was 236 min. The percentage of patients with satisfactory colon cleansing levels was 70%. The sensitivity, specificity, and diagnostic accuracy rates in detecting colorectal polyps with a size ≥ 6 mm were 76.9%, 75.0%, and 76.4%, respectively. Twelve patients (71%) evaluated the CCE procedure as more than “good” in the questionnaire, thus confirming the tolerability of our new regimen.

Research conclusions

This study shows the safety and utility of modified bowel preparation for CCE, which uses castor oil, and found that that it can achieve capsule excretion, colon cleansing, high tolerability of CCE preparation, and reduction of liquid laxative volume.

Research perspectives

A prospective multicenter trial is required to assess the safety and utility of castor oil–boosted bowel preparation for CCE.