A conflict of interest exists when a personal, financial, professional, or other relationship could influence, or appear to influence, a person's work or judgment. Having a conflict is not wrong in itself. Not telling the journal about it is the problem. Examples:

• Financial: funding, payment, shares, or other income related to the research or its results.
• Professional: working at the same institution or on the same project as someone involved in the manuscript, or competing with them.
• Personal: family, friendship, or a past dispute with someone involved.
• Academic: strong personal or ideological views that could affect the work.

• Authors must declare any conflict of interest in the Conflict of Interest statement of the manuscript, between the Conclusion and the References.
• If there is none, write: "No potential conflict of interest was reported by the author(s)."
• Authors must also state the source of funding, or that there was none, in the Funding statement.
• Authors should name people who should not review the manuscript if there is a conflict.

• Reviewers must tell the editor if they have a conflict with the authors or the topic, and decline the review.
• Reviewers must not use unpublished information from a manuscript for their own benefit, and must keep the manuscript confidential.

• Editors must not handle a manuscript if they have a conflict with the authors, such as working together or being at the same institution.
• Manuscripts submitted by an editor or board member are handled by another editor who has no conflict, and the person is not involved in the review or decision.
• Editors must keep manuscripts and reviewer identities confidential.

If a conflict of interest is found after submission or publication, the editors ask the authors to explain. Depending on the case, the journal may ask for a correction, reject the manuscript, or retract the article. See Research Misconduct and Correction and Retraction.