Key Takeaways
- Not following fasting instructions can interfere with the procedure and may increase safety risks.
- Failing to review medications with your healthcare team can cause avoidable complications.
- Inadequate bowel preparation can affect the quality of a lower gastrointestinal examination.
- Understanding transportation, timing, and aftercare instructions can make preparation smoother.
Preparing for an endoscopy involves more than arriving at the clinic. Proper endoscopy preparation may include fasting, medication adjustments, bowel preparation, transportation, and other instructions.
Common mistakes include eating or drinking during fasting, taking medications without checking, completing bowel preparation incorrectly, misunderstanding appointment instructions, failing to arrange transport, and not reporting relevant medical information. Following your healthcare team’s instructions helps the examination proceed safely.
1. Eating or Drinking During the Fasting Period
One of the most important preparation requirements for an endoscopy is fasting. Food or liquid remaining in the stomach can interfere with the examination and may increase complications when sedation is used [1].
A common mistake is assuming that small amounts of food, milk, coffee, or other drinks will not matter. Fasting requirements vary depending on the procedure, sedation, and individual circumstances. Some may be allowed clear liquids until a specific time, while others receive different instructions.
Ask your clinic exactly when you should stop eating and drinking. Follow those endoscopy instructions rather than relying on general advice online. If you accidentally eat or drink after the required fasting time, tell the clinic before the procedure.
2. Not Asking About Medications
Some medications need special consideration before an endoscopy. Blood-thinning medicines, diabetes medications, and certain supplements can require specific instructions because fasting or the procedure may affect their use [2].
Do not stop prescribed medication on your own. Provide your healthcare team with a complete list of prescription medicines, over-the-counter products, vitamins, and supplements you take.
| Preparation issue | Why it matters | What to do |
| Eating or drinking too late | May affect safety or visibility | Follow fasting instructions |
| Medication changes | Some medicines require adjustment | Ask your doctor before changing them |
| Incomplete bowel preparation | May reduce visibility | Follow the bowel-prep schedule |
| Missing appointment details | Can cause delays | Confirm date, time, and arrival instructions |
| No transport arranged | Sedation may affect driving | Arrange an adult escort if required |
| Missing medical information | May affect safety | Tell your healthcare team about relevant conditions |
If you take diabetes medication, ask how to manage it while fasting. People using blood thinners should ask whether adjustment is necessary. Your doctor will consider your individual risks.
3. Completing Bowel Preparation Incorrectly
For a colonoscopy or other examination requiring a clear bowel, bowel preparation is essential. It usually involves a prescribed laxative solution and dietary restrictions.
A frequent mistake is stopping the preparation because the solution is unpleasant or bowel movements appear clear enough. This can leave stool in the bowel, making it harder to see the lining and potentially requiring the procedure to be repeated [3].
Follow the exact timing and dosage provided by your clinic. Stay hydrated according to your instructions. If you experience severe vomiting, dizziness, significant weakness, or cannot complete the preparation, contact your healthcare provider.
4. Misunderstanding the Appointment Instructions
Another common mistake is overlooking practical details. Patients may arrive too late, forget identification or medical documents, or misunderstand where and when they need to report.
Before your endoscopy procedure, confirm the appointment date, arrival time, location, fasting instructions, and required documents. Ask whether you need to arrive earlier for registration or preparation.
If the clinic provides written instructions, read them carefully and keep them accessible [4]. Do not assume preparation instructions from a previous procedure are identical to those for your current appointment. Requirements vary by examination and sedation.
5. Failing to Arrange Transportation After Sedation
If sedation is planned, arranging transportation is an important part of preparation. Sedative medicines can temporarily affect alertness, coordination, judgment, and reaction time [5].
A common mistake is planning to drive yourself home because you feel awake after the procedure. Feeling alert does not necessarily mean sedation effects have completely worn off.
Ask whether you need an adult to accompany you home or remain with you after your endoscopy procedure. Follow instructions about driving, operating machinery, alcohol, work, and other activities. If an escort is required, arrange this before the procedure.
6. Not Reporting Medical Conditions, Allergies, or Previous Problems
Your healthcare team needs accurate information to assess whether the planned preparation and procedure are appropriate [6]. Failing to mention allergies, medical conditions, or previous reactions to sedation can create avoidable safety concerns.
Tell your doctor about heart or lung conditions, diabetes, kidney problems, pregnancy, medication allergies, previous anaesthetic or sedation problems, and other significant medical history. Mention previous difficulty with bowel preparation or complications.
If you develop a new illness, fever, severe abdominal pain, vomiting, or another significant problem before the endoscopy procedure, contact the clinic.
What Should You Do If You Make a Preparation Mistake?
If you realise that you have not followed an instruction correctly, do not assume that the procedure must automatically be cancelled. Contact the clinic as soon as possible and explain what happened.
Tell the healthcare team what you ate or drank, when you took medication, how much bowel preparation you completed, or what symptoms developed. They can advise whether to continue preparing, change the timing, or reschedule.
Do not hide a preparation mistake. Early communication helps the healthcare team make an appropriate decision.
How Can You Make Preparation Easier?
Start your endoscopy preparation as soon as you receive the instructions. Write down important times, including when to stop eating, take preparation medicines, and arrive.
Keep medications and information organised, and arrange transportation in advance if sedation will be used. If bowel preparation is required, stay near a toilet and follow the recommended fluid instructions.
Ask questions if anything is unclear. Your healthcare team’s advice should take priority over general information.
Conclusion
Good endoscopy preparation can help an endoscopy proceed safely and allow useful results. Common mistakes involve fasting, medication management, bowel preparation, appointment instructions, transportation, and incomplete medical information.
If you are unsure about any part of your preparation, contact your clinic before the procedure. Following personalised instructions and reporting problems promptly can help reduce avoidable delays and support a smoother examination experience.
References
- National Health Service. (2026). Gastroscopy. NHS. https://www.nhs.uk/tests-and-treatments/gastroscopy/
- Acosta, R. D., Abraham, N. S., Chandrasekhara, V., Chathadi, K. V., Early, D. S., Eloubeidi, M. A., Evans, J. A., Faulx, A. L., Fisher, D. A., Fonkalsrud, L., Khashab, M. A., Lightdale, J. R., Muthusamy, V. R., Pasha, S. F., Saltzman, J. R., Shergill, A. K., Wang, A., Cash, B. D., & DeWitt, J. M. (2016). The management of antithrombotic agents for patients undergoing GI endoscopy. Gastrointestinal Endoscopy, 83(1), 3–16. https://doi.org/10.1016/j.gie.2015.09.035.
- Jacobson, B. C., Anderson, J. C., Burke, C. A., Dominitz, J. A., Gross, S. A., May, F. P., Patel, S. G., Shaukat, A., & Robertson, D. J. (2025). Optimizing bowel preparation quality for colonoscopy: Consensus recommendations by the US Multi-Society Task Force on Colorectal Cancer. Gastrointestinal Endoscopy, 101(4), 702–732. https://doi.org/10.1016/j.gie.2025.02.010.
- University College London Hospitals NHS Foundation Trust. (2026). Gastroscopy: A guide for patients. https://www.uclh.nhs.uk/patients-and-visitors/patient-information-pages/gastroscopy-guide-patients
- Early, D. S., Lightdale, J. R., Vargo, J. J., II, Acosta, R. D., Chandrasekhara, V., Chathadi, K. V., Evans, J. A., Fisher, D. A., Fonkalsrud, L., Hwang, J. H., Khashab, M. A., Muthusamy, V. R., Pasha, S. F., Saltzman, J. R., Shergill, A. K., Cash, B. D., & DeWitt, J. M. (2018). Guidelines for sedation and anesthesia in GI endoscopy. Gastrointestinal Endoscopy, 87(2), 327–337. https://doi.org/10.1016/j.gie.2017.07.018.
- Guy’s and St Thomas’ NHS Foundation Trust. (2026). Gastroscopy: Having a gastroscopy. https://www.guysandstthomas.nhs.uk/health-information/gastroscopy/having-gastroscopy
