Definition · Plain-language
Good Clinical Practice (GCP)
Good Clinical Practice (GCP) is the international ethical and scientific quality standard for designing, conducting, recording and reporting clinical trials involving human participants.
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Two inseparable aims: participant protection and data credibility
GCP rests on two pillars that cannot be separated. The first is the protection of the rights, safety and well-being of trial participants, grounded in the principles of the Declaration of Helsinki and given effect through informed consent and independent ethics-committee review. The second is the credibility of the trial data, so regulators and the public can trust the results. GCP treats these as equally essential: a trial that produces clean data while mistreating participants is as unacceptable as one that protects participants but yields unreliable results.
Key roles and documents
GCP defines responsibilities for the sponsor (who initiates and finances the trial), the investigator (who conducts it at a site) and the independent ethics committee or institutional review board (which safeguards participants). Central documents include the trial protocol, the investigator’s brochure, signed informed-consent forms and source records. The principle of attributable, contemporaneous and accurate recording — shared with the ALCOA data-integrity framework — ensures that case report forms can be reconciled with original source data during monitoring and inspection.
From E6(R2) to E6(R3)
The authoritative GCP reference is the ICH E6 guideline. Its R2 revision introduced explicit expectations for risk-based quality management and trial oversight. The R3 revision, reaching its adopted (Step 4) form in 2025, restructures the guideline to be more principles-based and media-neutral, reflecting decentralised trials, electronic data sources and modern technologies. Adoption timelines vary by region as authorities such as the FDA, EMA and MHRA implement the updated text into their own frameworks.
Key facts
At a glance
- Definition: international ethical and scientific standard for clinical trials
- Twin aims: protect participants’ rights/safety and ensure credible data
- Defining reference: ICH E6 (E6(R2) → modernised E6(R3), 2025)
- Ethical foundation: the Declaration of Helsinki
- Key roles: sponsor, investigator, independent ethics committee/IRB
- Core control: informed consent and traceable source data
Common misconceptions
What people often get wrong
Often heard: GCP is only about getting clean, usable trial data.
Actually: Data credibility is only half of GCP. Equal weight is given to protecting the rights, safety and well-being of human participants through informed consent and independent ethics review; both aims must be satisfied.
Often heard: GCP is a law passed by a single country.
Actually: GCP is an international harmonised standard, principally the ICH E6 guideline, that individual authorities such as the FDA, EMA and MHRA adopt into their own regulatory frameworks. It is a guideline implemented regionally, not one national statute.
Often heard: GCP and GLP are interchangeable terms for trial quality.
Actually: They cover different stages. GCP governs clinical trials in human participants, whereas GLP governs non-clinical laboratory and animal safety studies. Confusing them misstates which standard applies to a given study.
Going deeper
