If you have just joined a pharmaceutical manufacturer, a QA or QC lab or a warehouse that handles medicines, you will hear the letters GMP many times a day. Good Manufacturing Practice is the set of rules that makes sure every batch of a medicine is made and controlled to the right quality. This guide covers what new starters need to understand in their first weeks.
Why GMP exists
A patient cannot test the tablet they swallow. They rely on the manufacturer to get every step right, every time. Testing a finished batch only checks a small sample, so GMP builds quality into everything: people, premises, equipment, materials, processes and records. In the EU, the rules are in EudraLex Volume 4; in the UK, the MHRA applies equivalent UK GMP; in the US, the FDA enforces cGMP in 21 CFR Parts 210 and 211.
1. If it is not written down, it did not happen
Records are how a company proves it followed its approved procedures. Fill them in at the time you do the task, in indelible ink, and correct mistakes with a single line so the original stays readable, then initial and date the change. Never back-date, pre-fill or sign for someone else. Regulators treat unreliable records as seriously as a faulty product.
2. Data integrity: ALCOA+
Inspectors expect data to be attributable, legible, contemporaneous, original and accurate, plus complete, consistent, enduring and available. In practice that means your own login for every system, no shared passwords and never deleting or overwriting a result, even one that fails.
3. Follow the procedure, or raise a deviation
Every GMP task has a standard operating procedure (SOP). If you cannot follow it, or something unexpected happens, stop and report it. A deviation reported honestly is a normal part of quality management. A deviation hidden is a serious breach.
4. Hygiene and contamination control
People are the biggest source of contamination. Follow the gowning rules for each area, wash and sanitise your hands, report illness or open wounds, and keep personal items out of production areas. In sterile manufacturing, EU GMP Annex 1 sets strict cleanroom grades and requires a site-wide contamination control strategy.
5. Changes need control
Changing a machine setting, a supplier or a procedure without approval can affect product quality in ways nobody predicted. That is why every GMP-relevant change goes through change control, where its impact is assessed and approved by Quality Assurance first.
6. Be ready for an inspection every day
Inspections can be announced or unannounced. If an inspector asks you a question, answer honestly and simply, show the evidence (a logbook, a label, an SOP) and say “I don’t know, but I can find out” rather than guessing.
Your first-month checklist
- Read and sign the SOPs for your role before doing the task.
- Ask how deviations are reported in your area.
- Learn the gowning and hygiene rules for every room you enter.
- Check that every instrument you use has a valid calibration label.
- Find out who your QA contact is.
Want a structured grounding in GMP? Our GMP Professional Certificate covers the rules, documentation and data integrity, deviations and CAPA, validation, Annex 1 and inspection readiness in 8 self-paced modules.