The Ultimate Guide to Gastroscopy and Colonoscopy for Dogs and Cats: Procedure and Costs

DigestiveQ&AMeongsiljang Veterinary Advisory Board

Endoscopy is a precise diagnostic procedure that allows veterinarians to directly visualize the cause of vomiting, diarrhea, or bloody stools in pets. We’ve compiled everything pet owners need to know about the procedure, including preparation, costs, and recovery.

What Is Gastrointestinal Endoscopy for Pets?

A veterinary endoscope camera and an anesthetized dog

Endoscopy for pets is a precise gastrointestinal examination that involves inserting a thin, flexible camera tube through the mouth or anus to directly visualize the mucosal lining of the esophagus, stomach, duodenum, or colon. Its key advantage is the ability to identify foreign bodies, tumors, and inflammation in real time while simultaneously performing biopsies. It serves as the most definitive diagnostic tool for cases of chronic vomiting, diarrhea, or bloody stools when the underlying cause remains unclear despite X-rays and ultrasound.

When Is Endoscopy Recommended?

Veterinarians typically recommend endoscopy when chronic gastrointestinal symptoms persist despite other diagnostic tests. Common indications include chronic vomiting, weight loss, bloody or black tarry stools, difficulty swallowing, and suspected ingestion of foreign bodies. In cases of foreign body ingestion, endoscopic removal via the esophagus or stomach can often avoid open surgery, leading to faster recovery and significantly reducing the burden on pet owners. Veterinary textbooks also note that esophageal foreign bodies generally have a favorable prognosis after non-surgical removal. In cats, endoscopy is frequently used when ingestion of linear foreign bodies such as string or needles is suspected.

Gastroscopy vs. Colonoscopy: A Quick Comparison

Item	Gastroscopy	Colonoscopy
Access route	Mouth → esophagus → stomach → duodenum	Anus → rectum → colon
Main indications	Chronic vomiting, foreign body, gastritis	Bloody stool, colitis, tumor
Fasting time	12 hours or more	24–36 hours + enema
Exam time	30–60 minutes	45–90 minutes
Anesthesia	General anesthesia required	General anesthesia required

The time required may vary depending on the scope of the exam and the hospital's equipment.

Pre-Endoscopy Preparation — Fasting and Pre-Exam Tests

The most important thing on the day of the exam is fasting properly. If there is still food in the stomach, it can block the view and make the exam impossible.

Fasting time: At least 12 hours for a gastroscopy, and 24–36 hours for a colonoscopy.

Water restriction: Stop giving water 2–3 hours before the exam.

Pre-exam tests: Blood tests, an ECG, and a chest X-ray are done to check if anesthesia is safe.

Enema: For a colonoscopy, the colon needs to be cleared with several enemas starting the day before.

According to veterinary internal medicine textbooks, if there is still material in the intestines, the accuracy of observing the mucosa drops significantly.

A fasting dog before endoscopy and its water bowl

Important Information on Anesthesia

Gastrointestinal endoscopy requires general anesthesia. The scope cannot be inserted while the patient is conscious, and any movement risks tearing the mucosa. Older dogs and pets with heart or respiratory conditions face higher anesthesia risks. Your veterinarian will select the appropriate anesthetic agent and dosage based on weight, age, and underlying health conditions. Be sure to review pre-anesthetic test results and ask any questions you may have beforehand.

How Is the Procedure Performed?

Here’s how the procedure unfolds on the day of the exam:

Step 1 – Hospitalization and General Anesthesia: After securing vascular access, anesthesia is induced, and endotracheal intubation is performed to assist with breathing.

Step 2 – Positioning: The patient is placed on their side to ensure the proper angle for endoscope passage.

Step 3 – Endoscope Insertion: The camera-equipped tube is inserted through the mouth or anus, and a small amount of air is introduced to expand the organs for better visibility.

Step 4 – Observation and Biopsy: Images of any abnormal areas are captured, and if necessary, tissue samples are collected using forceps.

Step 5 – Recovery: Oxygen levels and body temperature are closely monitored until the patient fully wakes from anesthesia.

The veterinary team monitoring vital signs during an endoscopic examination

Conditions Detectable via Endoscopy

Endoscopy can identify a wide range of conditions.

Gastritis and gastric ulcers: Direct visualization of mucosal hyperemia, bleeding, and ulcers

Foreign bodies: Immediate removal of items such as bones, toys, hairballs, and needles

Inflammatory bowel disease (IBD): Definitive diagnosis via biopsy

Gastric and intestinal tumors: Differentiation of polyps, adenocarcinomas, and lymphomas

Esophagitis and esophageal stricture: Diagnosis of reflux esophagitis

Infectious enteropathy: Identification of mucosal abnormalities and differentiation of infectious causes, such as fungi and parasites, through biopsy

Veterinary internal medicine textbooks classify endoscopic biopsy as the "definitive diagnostic step" for differentiating the causes of chronic vomiting and diarrhea.

Post-Exam Observation Points

Most pets go home the same day or the next. Still, keep a close eye on them for the first 24–48 hours after they return. Their belly may look distended from the air introduced during the procedure, and they might experience mild nausea. These signs usually resolve within a day. However, if repeated vomiting, bloody stools, severe abdominal pain, or lethargy persist for more than 12 hours, contact your veterinarian immediately, as these could indicate complications such as a perforation.

Post-Exam Recovery and Dietary Management

Once your pet has fully recovered from anesthesia, you can usually start offering small amounts of water after 4 to 6 hours. Feeding should begin with a small portion of easily digestible prescription food, typically 6 to 12 hours later, following your veterinarian’s instructions.

Recovery Care Tips:

Same day: Rest in a quiet, warm place; no walks or baths.

Next day: Start with half the usual food amount and gradually increase over 2 to 3 days.

Biopsy results: Pathology results will be available in 3 to 7 days, and the treatment plan will be determined based on those findings.

Most pets return to their normal condition within 2 to 3 days.

A dog recovering comfortably at home after an endoscopy.

Reviewed by a veterinarian

Dr. Tony — Punnawat Phongkittirak

Veterinarian

A veterinarian who majored in veterinary medicine at Khon Kaen University, Thailand, and completed the IVSA program at North Carolina State University in the United States. Drawing on clinical experience at animal hospitals, he works in the pet healthcare field and is dedicated to building a digital care environment that connects pet parents with veterinarians.

Frequently Asked Questions

How much do an upper endoscopy and a colonoscopy cost?

Costs vary significantly depending on the clinic, location, and whether a biopsy is performed, so it’s best to consult your veterinarian for an accurate estimate. Please note that anesthesia, pre-anesthetic testing, and biopsy fees are billed separately. We recommend requesting a detailed quote in advance so you can review each itemized cost.

Can all foreign objects be removed using an endoscope?

It depends on the size and location of the object. Small, round objects in the stomach can usually be removed, but sharp objects or those that have moved into the intestines may require surgery. We'll first check the location with an X-ray before deciding on the best course of action.

Can senior dogs also undergo endoscopic examinations?

What matters most is not a dog’s age, but the condition of its heart, kidneys, and liver. If pre-anesthetic blood work and an electrocardiogram indicate that anesthesia is safe, even senior dogs can undergo the procedure with confidence. If your dog has underlying health conditions, choose a clinic with a veterinary anesthesiologist on staff.

When will the biopsy results be available?

In-house tests at the clinic typically take 2–3 days, while samples sent to an external pathology lab may take 5–10 days. If a malignant tumor is suspected, additional immunohistochemical staining can extend the wait to over two weeks. Since the treatment plan varies significantly depending on the results, be sure to listen carefully to your veterinarian’s detailed explanation.

Can other tests be used instead of an endoscopy?

Ultrasound, X-rays, and CT scans are excellent for visualizing the overall structure of organs, but an endoscope is essential for directly examining the mucosa or collecting tissue samples. Since the appropriate tests vary depending on symptoms and suspected conditions, please consult your veterinarian to select the most suitable diagnostic approach for your pet.

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References

[1] Clinical Medicine of the Dog and Cat, 4th Ed - Chapter 9 Gastrointestinal Disorders

[2] Notes on Canine Internal Medicine, 4th Ed - Oesophageal and Gastric Disorders

[3] Veterinary Surgical Oncology, 2nd Ed - Endoscopic Diagnosis of GI Tumors