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Endoscopy, Gastroscopy and Colonoscopy Explained

By 25/04/2026May 1st, 2026No Comments

If your GP has referred you for an endoscopy, gastroscopy or colonoscopy, it is natural to have questions about what each procedure involves and why one test may be recommended over another. These terms are sometimes used together, and this can make things confusing for patients.

In simple terms, endoscopy is a broad term for procedures that use a small camera to look inside the body. Gastroscopy is a type of endoscopy that looks at the upper part of the digestive system, including the oesophagus, stomach and first part of the small bowel. Colonoscopy is another type of endoscopy that looks at the large bowel and rectum.

Direct Endoscopy provides a range of digestive health procedures, including gastroscopy, colonoscopy and capsule endoscopy. Each procedure has a different purpose, and the right test depends on your symptoms, medical history, screening results and your doctor’s assessment.

This guide explains the difference between endoscopy, gastroscopy and colonoscopy, when each procedure may be recommended, what they can help detect, and what to expect before, during and after the procedure.

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What is endoscopy?

Endoscopy is a general medical term for procedures that allow a doctor to look inside the body using a small camera. In digestive health, endoscopy usually refers to procedures that examine parts of the gastrointestinal tract, such as the oesophagus, stomach, small bowel, large bowel or rectum.

According to Healthdirect’s explanation of endoscopy, an endoscopy gives your doctor a direct view of internal organs and can help diagnose and treat some conditions. The endoscope is usually a thin, flexible tube with a light and camera at the tip, and images are viewed on a screen during the procedure.

Endoscopy is not one single test. It is an umbrella term. A gastroscopy, colonoscopy and capsule endoscopy are all examples of endoscopic procedures, but they examine different parts of the digestive system and are used for different reasons.

For patients, the most important thing to understand is which part of the digestive tract needs to be examined. Symptoms in the upper digestive tract may require gastroscopy. Symptoms in the lower digestive tract may require colonoscopy. Suspected small bowel problems may sometimes require capsule endoscopy.

What is gastroscopy?

Gastroscopy is a procedure used to examine the upper part of the digestive system. This usually includes the oesophagus, stomach and duodenum, which is the first part of the small bowel.

During a gastroscopy, a thin, flexible tube with a camera is gently passed through the mouth and down into the upper digestive tract. The doctor can view the lining of the oesophagus, stomach and duodenum on a screen. If needed, small tissue samples, known as biopsies, can be taken during the procedure.

Healthdirect’s gastroscopy guide explains that gastroscopy is also known as upper endoscopy and is used to look inside the oesophagus, stomach and first part of the small bowel.

Gastroscopy is commonly used to investigate symptoms such as reflux, heartburn, swallowing difficulties, nausea, vomiting, upper abdominal pain, unexplained weight loss, anaemia, or suspected ulcers. It may also be used to assess conditions such as gastritis, coeliac disease, Barrett’s oesophagus or upper gastrointestinal bleeding.

Direct Endoscopy provides gastroscopy in Melbourne across multiple locations, with specialist gastroenterologists performing the procedure in accredited hospital settings.

What is colonoscopy?

Colonoscopy is a procedure used to examine the large bowel, also called the colon, and the rectum. It is one of the most important procedures used to investigate bowel symptoms and follow up positive bowel screening results.

During a colonoscopy, a thin, flexible camera called a colonoscope is gently passed through the rectum and guided around the large bowel. The doctor can view the bowel lining on a screen and look for polyps, inflammation, bleeding, cancer, or other abnormalities.

Better Health Channel’s colonoscopy information explains that colonoscopy is a medical procedure used to examine the large bowel, using a flexible tube with a small camera and light.

One of the important benefits of colonoscopy is that polyps can often be removed during the procedure. Polyps are small growths in the bowel lining. Many are benign, but some types can develop into bowel cancer over time if they are not removed.

A colonoscopy may be recommended for symptoms such as rectal bleeding, persistent changes in bowel habits, unexplained iron deficiency, unexplained abdominal pain, or a positive bowel screening test. It may also be recommended for people with a personal history of polyps, inflammatory bowel disease or certain family history risk factors.

What is capsule endoscopy?

Capsule endoscopy is a different type of endoscopy. Instead of using a flexible tube, capsule endoscopy involves swallowing a small capsule that contains a camera. As the capsule travels naturally through the digestive tract, it takes images that are transmitted to a recording device.

Capsule endoscopy is most commonly used to examine the small bowel. The small bowel can be difficult to assess with standard gastroscopy or colonoscopy because it sits between the stomach and large bowel. Capsule endoscopy can help detect possible causes of small bowel bleeding, inflammation, ulcers or other abnormalities.

Direct Endoscopy’s capsule endoscopy page explains that this procedure uses a small ingestible camera capsule to capture images of the small bowel, an area that can be difficult to reach with traditional endoscopy.

Capsule endoscopy is not the same as gastroscopy or colonoscopy. It does not usually allow tissue samples to be taken or polyps to be removed. Instead, it is mainly a diagnostic imaging test that helps your specialist see parts of the small bowel that may otherwise be difficult to assess.

Endoscopy vs gastroscopy: what is the difference?

The difference between endoscopy and gastroscopy is that endoscopy is the broad term, while gastroscopy is a specific type of endoscopy.

Endoscopy can refer to many procedures that use a camera to look inside the body. In digestive health, the term may be used to describe gastroscopy, colonoscopy, capsule endoscopy or other procedures. Gastroscopy specifically refers to examining the upper digestive tract through the mouth.

This is why some patients may hear the terms “endoscopy” and “gastroscopy” used almost interchangeably. In everyday medical conversations, a doctor may refer to an “upper endoscopy” or simply an “endoscopy” when they mean gastroscopy. However, technically, gastroscopy is one type of endoscopy.

If you are unsure what procedure you have been referred for, ask your GP or specialist to confirm whether they mean gastroscopy, colonoscopy, capsule endoscopy or another test. This matters because the preparation, procedure and part of the body examined can be different.

Gastroscopy vs colonoscopy: what is the difference?

Gastroscopy and colonoscopy are both endoscopic procedures, but they examine different parts of the digestive system.

Gastroscopy examines the upper digestive tract. This includes the oesophagus, stomach and duodenum. The camera enters through the mouth. It is often used for symptoms such as reflux, heartburn, difficulty swallowing, upper abdominal pain, nausea, vomiting, suspected ulcers or upper gastrointestinal bleeding.

Colonoscopy examines the lower digestive tract, particularly the large bowel and rectum. The camera enters through the rectum. It is often used for symptoms such as rectal bleeding, changes in bowel habits, unexplained iron deficiency, abdominal pain, positive bowel screening results, or surveillance after bowel polyps.

The preparation is also different. Gastroscopy usually requires fasting for several hours before the procedure. Colonoscopy requires bowel preparation to empty the bowel so the lining can be seen clearly.

Both procedures are commonly performed as day procedures, and sedation is often used to keep patients comfortable. Your doctor will recommend the procedure based on your symptoms and the part of the digestive system that needs to be assessed.

A gastroscopy may be recommended when symptoms suggest a problem in the upper digestive tract. These symptoms can include persistent reflux, frequent heartburn, difficulty swallowing, upper abdominal pain, nausea, vomiting, bloating, unexplained weight loss, vomiting blood or black stools that may suggest bleeding.

Gastroscopy can help diagnose several conditions. These may include oesophagitis, gastritis, stomach ulcers, duodenal ulcers, coeliac disease, Barrett’s oesophagus, strictures, inflammation, infection or signs of upper gastrointestinal bleeding.

In some cases, biopsies are taken during gastroscopy even if the lining looks normal. For example, biopsies may be taken to check for coeliac disease, Helicobacter pylori infection or microscopic inflammation.

If your GP has recommended a gastroscopy, it is usually because your symptoms, blood tests or medical history suggest that your upper digestive tract should be examined more closely.

A colonoscopy may be recommended when symptoms suggest a problem in the large bowel or rectum. These symptoms can include rectal bleeding, blood in the stool, persistent diarrhoea, constipation, a change in bowel habits, unexplained iron deficiency, abdominal pain, unexplained weight loss or a feeling that the bowel is not emptying properly.

Colonoscopy is also commonly recommended after a positive bowel screening test. The home screening test can detect hidden blood in the stool, but it cannot show where the blood has come from. Colonoscopy allows the doctor to examine the bowel lining and identify the cause of bleeding.

Colonoscopy may also be used for surveillance. This means monitoring people who have had previous bowel polyps, bowel cancer, inflammatory bowel disease or certain family history risk factors.

For patients who need a colonoscopy in Melbourne, Direct Endoscopy provides services across multiple locations, including Frankston, Hampton, Bayswater, Narre Warren and Rosebud.

Capsule endoscopy may be recommended when a doctor needs to examine the small bowel. The small bowel is a long section of the digestive tract between the stomach and the large bowel. It can be difficult to fully assess using standard gastroscopy or colonoscopy.

Capsule endoscopy is often used when there is suspected small bowel bleeding, unexplained iron deficiency anaemia, suspected Crohn’s disease affecting the small bowel, or symptoms that suggest a small bowel problem after other tests have not provided a clear answer.

The procedure involves swallowing a small camera capsule. The capsule travels through the digestive system and takes images as it moves. These images are recorded and later reviewed by the specialist.

Capsule endoscopy is generally less invasive than tube-based endoscopy, but it is not suitable for every patient. Some people may need assessment first to reduce the risk of capsule retention, particularly if there is a known or suspected narrowing in the bowel. Your specialist will advise whether capsule endoscopy is appropriate for your situation.

Can gastroscopy and colonoscopy be done together?

Yes, gastroscopy and colonoscopy can sometimes be performed during the same appointment. This may be recommended when symptoms, blood tests or medical history suggest that both the upper and lower digestive tract should be examined.

For example, a patient with unexplained iron deficiency anaemia may need investigation of both the upper digestive tract and the large bowel. A patient with mixed symptoms, such as reflux and changes in bowel habits, may also be referred for both procedures depending on the clinical situation.

Having both procedures together may reduce the need for two separate appointments, two separate admissions and two separate sedation events. However, it is not necessary for every patient. Your GP or specialist will decide whether one procedure or both procedures are appropriate.

If both procedures are being performed together, you will usually need to follow colonoscopy bowel preparation instructions, as well as fasting instructions. The clinic will provide specific preparation instructions before your appointment.

What can these procedures detect?

Gastroscopy, colonoscopy and capsule endoscopy can each help detect different digestive health conditions. The findings depend on which part of the digestive system is being examined.

Gastroscopy can help detect:

  • Reflux-related inflammation
  • Oesophagitis
  • Gastritis
  • Stomach or duodenal ulcers
  • Coeliac disease
  • Barrett’s oesophagus
  • Helicobacter pylori infection
  • Upper gastrointestinal bleeding
  • Narrowing or strictures of the oesophagus

Colonoscopy can help detect:

  • Bowel polyps
  • Bowel cancer
  • Inflammation in the large bowel
  • Ulcerative colitis or Crohn’s disease affecting the colon
  • Diverticular disease
  • Possible causes of rectal bleeding
  • Possible causes of persistent bowel habit changes
  • Possible causes of iron deficiency anaemia

Capsule endoscopy can help detect:

  • Small bowel bleeding
  • Small bowel inflammation
  • Small bowel ulcers
  • Possible small bowel Crohn’s disease
  • Other abnormalities in areas not easily reached by standard gastroscopy or colonoscopy

These procedures do not all do the same thing. The best test depends on where the suspected problem is located and what your doctor is trying to find out.

Preparation differences between gastroscopy, colonoscopy and capsule endoscopy

Preparation is one of the main differences between gastroscopy, colonoscopy and capsule endoscopy.

Gastroscopy usually requires fasting. This means not eating for a certain period before the procedure and following instructions about when to stop drinking fluids. Fasting helps ensure the stomach is empty so the doctor can see clearly and reduces the risk of complications during sedation.

Colonoscopy requires bowel preparation. This involves taking a bowel preparation solution to empty the bowel before the procedure. Good bowel preparation is important because stool can hide polyps or other abnormalities. If the bowel is not clean enough, the procedure may be less accurate or may need to be repeated.

Capsule endoscopy preparation can vary depending on the patient and the specialist’s instructions. It may involve fasting and sometimes a bowel preparation or medication to improve visibility. You will also wear a recording device while the capsule takes images.

Direct Endoscopy provides patient preparation information for gastroscopy preparation, colonoscopy preparation and capsule endoscopy preparation.

Sedation and comfort during endoscopy procedures

Many patients feel nervous before an endoscopy procedure. This is understandable, especially if it is your first time having a gastroscopy or colonoscopy.

Gastroscopy and colonoscopy are commonly performed with sedation or anaesthesia to keep patients comfortable. The level of sedation depends on the procedure, patient factors, facility protocols and medical advice. Most patients do not remember much of the procedure afterwards.

The Australian and New Zealand College of Anaesthetists explains that endoscopy procedures, including gastroscopy and colonoscopy, are frequently performed as day-stay cases.

Capsule endoscopy is different because it usually does not require sedation. The patient swallows the capsule and wears a recording device while the capsule travels through the digestive tract. The capsule passes naturally in a bowel motion.

If you are anxious about the procedure, tell your doctor or the clinic. They can explain what to expect, how sedation works, and what you need to do before and after the appointment.

What happens after the procedure?

After gastroscopy or colonoscopy, you will usually be monitored while the sedation wears off. You may feel drowsy, so you will need someone to take you home. You should not drive, operate machinery or make important decisions for the rest of the day if you have had sedation.

Your doctor will usually explain the initial findings after the procedure. If biopsies or polyps were taken, final pathology results may take longer. Your follow-up plan will depend on what was found.

After gastroscopy, some patients may have a mild sore throat or bloating. After colonoscopy, some patients may feel bloated or pass wind as air or carbon dioxide used during the procedure leaves the bowel. These symptoms usually settle.

After capsule endoscopy, you will return the recording equipment as instructed. The capsule is disposable and usually passes naturally. Your specialist will review the images and provide results later.

Seek medical advice promptly if you develop severe abdominal pain, persistent vomiting, fever, heavy bleeding, chest pain, shortness of breath or any symptoms that concern you after the procedure.

Which test do you need?

The right test depends on your symptoms and what your doctor is trying to investigate. If your symptoms are mainly in the upper digestive tract, such as reflux, heartburn, difficulty swallowing or upper abdominal pain, your doctor may recommend gastroscopy.

If your symptoms involve the lower bowel, such as rectal bleeding, changes in bowel habits, unexplained iron deficiency or a positive bowel screening test, your doctor may recommend colonoscopy.

If there is concern about the small bowel, especially where gastroscopy and colonoscopy do not explain symptoms or bleeding, capsule endoscopy may be considered.

It is important not to choose the procedure based only on symptoms you read online. Many digestive symptoms overlap. For example, abdominal pain can come from many different parts of the digestive system. Your GP or specialist will consider your symptoms, age, medical history, family history, blood tests, stool tests and previous investigations before recommending the most appropriate test.

How Direct Endoscopy can help

Direct Endoscopy provides specialist gastroenterology and endoscopy services across multiple Melbourne locations, including Frankston, Hampton, Bayswater, Narre Warren and Rosebud. The team performs a range of procedures, including gastroscopy, colonoscopy and capsule endoscopy.

If your GP has referred you for a procedure, Direct Endoscopy can assist with booking, preparation instructions, the procedure itself and follow-up guidance. Patients can view all Direct Endoscopy locations on the locations page.

For upper digestive symptoms, you can learn more about gastroscopy services in Melbourne. For bowel symptoms, positive bowel screening results or bowel polyp surveillance, you can read more about colonoscopy services in Melbourne. For suspected small bowel concerns, you can learn more about capsule endoscopy.

Patients can also visit the Direct Endoscopy book online page for more information about appointment options.

Final thoughts

Endoscopy, gastroscopy and colonoscopy are related terms, but they do not all mean exactly the same thing. Endoscopy is the broad term for procedures that use a camera to look inside the body. Gastroscopy examines the upper digestive tract. Colonoscopy examines the large bowel and rectum. Capsule endoscopy uses a swallowable camera capsule to examine the small bowel.

Each test has a different role. Gastroscopy may be used for reflux, swallowing problems, upper abdominal pain or suspected ulcers. Colonoscopy may be used for rectal bleeding, changes in bowel habits, positive bowel screening results, bowel polyps or bowel cancer investigation. Capsule endoscopy may be used when the small bowel needs to be examined.

If you are unsure which procedure you need, speak with your GP or specialist. They can explain the reason for the referral and help you understand what to expect.

If you have been referred for gastroscopy, colonoscopy or capsule endoscopy, Direct Endoscopy can help guide you through the process with clear preparation instructions and specialist care.

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