Preparing for a colonoscopy means you’ll likely need to cut out fiber in the days leading up to your appointment and switch to a clear liquid diet starting the day before. You’ll also have to take laxatives as part of the prep.
A colonoscopy lets your doctor examine the inside of your colon and rectum. It’s one of the best ways for doctors to:
- Check for colon polyps
- Identify the cause of unusual symptoms
- Detect colon cancer
Even though the test itself is quick—and most people are under sedation so they don’t feel or remember anything—many still dread it. Recovery usually only takes a few hours, but the preparation can be unpleasant.
Why? Because your colon must be completely empty. To make that happen, you’ll take strong laxatives to flush out your system in the hours before the procedure. This means multiple bathroom trips, diarrhea, and some discomfort.
Your doctor will give you detailed instructions on how to prepare, what products to use, and what to expect. They’ll break it down day by day. While the timeline below gives a general idea, always check with your doctor if you have questions.
7 Days Before: Stock Up
Get a head start by shopping at least a week ahead. Here’s what you might need:
Laxatives
Some doctors prescribe specific laxatives, while others recommend over-the-counter (OTC) options. Buy what your doctor suggests, and call their office with any questions before prep day.
Moist Wipes
Regular toilet paper can get rough after frequent use. Try soothing wipes with aloe, vitamin E, or medicated options to ease irritation.
Diaper Cream
Some people apply diaper cream (like Desitin) before and during prep to prevent skin irritation from diarrhea and wiping.
Approved Foods & Sports Drinks
As your colonoscopy nears, you’ll switch to foods that make colon cleaning easier. Stock up on:
- Low-fiber foods
- Sports drinks
- Clear fruit juices
- Broths
- Gelatin
- Frozen pops
You’ll likely mix your laxative with a liquid—check how much you’ll need based on the type. Sports drinks or light-colored flavored drinks can help mask the taste.
5 Days Before: Adjust Your Diet
Start eating foods that pass through your system easily.
Low-Fiber Foods
Switch to these at least 5 days before:
- White bread
- Pasta
- Rice
- Eggs
- Lean meats (chicken, fish)
- Well-cooked veggies (no skins)
- Fruits (no skins or seeds)
Soft Foods
Eating soft foods 48 hours before may help. Try:
- Scrambled eggs
- Smoothies
- Vegetable purees/soups
- Soft fruits (like bananas)
Foods to Avoid
Skip hard-to-digest foods that could interfere with the procedure:
- Fried or fatty foods
- Tough meats
- Whole grains
- Nuts, seeds, popcorn
- Raw veggies or skins
- Fruits with seeds/skins
- Broccoli, cabbage, lettuce
- Corn
- Beans, peas
Medications
Ask your doctor if you should pause any prescriptions, vitamins, supplements, or OTC meds during prep.
Special Diet Considerations
Some health conditions require extra care:
- Heart/kidney failure, high blood pressure, or older adults may be at higher risk from electrolyte shifts.
- Diabetes/hypoglycemia may need closer glucose monitoring.
1 Day Before: Clear Liquids Only
The entire day before your colonoscopy, you’ll switch to a clear liquid diet so your colon empties fully. If it isn’t clear, your doctor might reschedule—meaning you’d have to prep all over again.
Stay hydrated: Aim for 8 ounces of clear liquids per waking hour. Water, sports drinks, broths, and gelatin are all fine.
The Night Before: Laxative Time
Your doctor will prescribe a strong laxative to clear any remaining waste. Most recommend a split dose:
- First half the night before.
- Second half 6 hours before the exam (or before midnight if your procedure is early).
Making the Laxative Easier to Drink
- Mix with sports drinks to mask the taste.
- Chill it—cold drinks go down smoother.
- Use a straw to bypass your taste buds.
- Chase it with lemon juice or hard candy.
- Add flavorings like ginger or lime.
What to Expect
Once the laxative kicks in, you’ll have frequent, urgent diarrhea, plus possible:
- Cramping
- Bloating
- Nausea/vomiting
- Irritated hemorrhoids
Staying Comfortable
- Camp out in the bathroom—bring a book, tablet, or other distraction.
- Use wipes/creams to soothe irritation.
2 Hours Before: Nothing by Mouth
Stop eating/drinking (even water) at least 3 hours before (some hospitals say longer). This prevents complications during sedation.
No smoking, gum, or anything oral.
The Bottom Line
Yes, colonoscopy prep (and recovery) can be uncomfortable. But skipping it means missing early signs of serious issues—like colon cancer. Follow your doctor’s instructions closely, and ask questions if unsure.
The good news? If everything looks normal, you might not need another one for 10 years.