What Kind of Soda Can I Drink Before a Colonoscopy?

November 19, 2025 •

4 min read

According to the American Cancer Society, a clear liquid diet is essential for a successful colonoscopy, and this often includes certain sodas. Knowing what kind of soda can I drink before a colonoscopy is key to proper bowel preparation and avoiding unnecessary complications or rescheduling the procedure.

Quick Summary

You can drink clear sodas like Sprite, 7-Up, and ginger ale on a colonoscopy prep diet, along with cola and diet cola, but you must avoid red or purple dyes and check specific guidelines from your doctor. Opt for carbonated beverages that you can see through to ensure proper bowel cleaning for the procedure.

Key Points

Clear is Key: Only consume sodas that are transparent or light in color, like Sprite, 7-Up, or ginger ale.
Cola is Acceptable: Many medical guidelines permit dark-colored sodas such as cola and diet cola, as they are considered clear liquids.
Avoid Red and Purple Dyes: Steer clear of any soda with red, purple, or dark blue dyes, as they can interfere with the examination and mimic blood.
Follow Your Doctor's Instructions: Always verify the specific list of approved beverages provided by your healthcare provider, as some guidelines may vary.
Stay Hydrated: Incorporating a variety of clear liquids, including soda, can help with hydration and make the bowel prep more palatable.
Chilling Improves Taste: Drinking your soda and other prep liquids when chilled can make the process easier to tolerate.

Approved Sodas for Your Colonoscopy Prep

During the day before your colonoscopy, you will follow a clear liquid diet, which means consuming only liquids that are transparent and contain no solid particles. This strict regimen is critical for ensuring your colon is completely clean, allowing your doctor to see the lining clearly and detect any polyps or other abnormalities. Fortunately, a variety of carbonated beverages are allowed to help make the prep process more tolerable.

Clear and Light-Colored Sodas

The most straightforward choices are sodas that are inherently clear or light in color. These beverages leave no residue behind and won't interfere with the visual clarity of the procedure. Good examples include Sprite, 7-Up, ginger ale, and seltzer. Many doctors' offices explicitly list these options in their preparatory instructions. Some also include clear fruit-flavored sodas, as long as they don't contain any red, purple, or dark blue dyes.

Dark-Colored Sodas: The Verdict on Cola

The most common question regarding sodas is whether dark-colored varieties like cola are acceptable. Most gastroenterologists and medical institutions agree that plain cola and diet cola are permissible. While the liquid is dark in the can, it is considered clear once consumed and does not leave a problematic residue in the colon. However, it is always best to double-check with your specific doctor, as some hospital guidelines may vary. Some practices, for example, might allow cola but not root beer, so confirming your specific instructions is crucial.

Why No Red, Purple, or Blue Dyes?

The reason for the strict avoidance of certain colors is simple: the dyes can stain the lining of the colon, creating a discoloration that could be mistaken for blood or other abnormalities during the examination. This can compromise the accuracy of the procedure, potentially leading to a missed diagnosis or the need for a repeat colonoscopy. This rule applies not just to sodas but to any liquid, gelatin, or popsicle you consume during the clear liquid diet phase. Therefore, any soda with a vibrant red, purple, or blue hue should be avoided completely.

Making Your Prep More Manageable

Sticking to a clear liquid diet for a full day can be challenging, but incorporating a variety of approved beverages, including soda, can help. Here are some tips:

Chill Your Drinks: Many patients find that the bowel prep solution itself and other liquids are more palatable when chilled. Keeping your soda cold in the refrigerator can make it more refreshing.
Variety is Key: Don't limit yourself to just one type of soda. Alternating between approved sodas like ginger ale and diet cola can prevent flavor fatigue and help you stay hydrated.
Mix It Up: In some cases, your doctor may suggest adding a powdered drink mix to the bowel prep solution. Opt for flavors that are green, yellow, or orange, and avoid red and purple.

Comparison Table: Approved vs. Unapproved Sodas


Feature	Approved Sodas	Unapproved Sodas
Examples	Sprite, 7-Up, Ginger Ale, Cola, Diet Cola, Club Soda	Any soda with red, purple, or dark blue dye
Why they're okay	They are clear or considered to leave no obstructive residue during the procedure.	The dyes can stain the colon lining, resembling blood or tissue.
Residue	Minimal to no residue left in the colon.	Can leave a deceptive residue that obscures the doctor's view.
Effect on Exam	Allows for clear visualization of the colon lining.	Can interfere with diagnostic accuracy, potentially leading to a repeat procedure.

What to Remember for a Successful Prep

While soda can provide a welcome diversion during your liquid-only diet, the ultimate goal is a successful procedure. Adherence to your doctor's specific instructions is paramount. If your bowel is not sufficiently cleansed, it may result in a non-diagnostic colonoscopy, forcing you to repeat the entire preparation and procedure.

Beyond soda, ensure you are drinking plenty of other clear liquids, such as clear broth, apple juice, white grape juice, and water, to stay hydrated and avoid fatigue. The carbonation in soda can also help with the feeling of fullness and add some variety to your day. Always confirm the specific color restrictions with your healthcare provider, as some practices have slightly different protocols.

Conclusion

In conclusion, you can drink a variety of sodas before a colonoscopy, but the key is to stick to clear or light-colored beverages that do not contain red, purple, or dark blue dyes. Options like Sprite, ginger ale, 7-Up, and even cola and diet cola are generally acceptable and can be a helpful part of your clear liquid diet. By following the proper dietary restrictions, you help ensure a successful procedure and an accurate result. Always consult the precise instructions provided by your medical team for the most reliable guidance. Remember that a small inconvenience now is a major health investment for the future. For more details on colonoscopy preparation, you can visit a reliable health resource like the American Cancer Society.

Frequently Asked Questions

Yes, many diet sodas are permissible, including diet cola, as long as they don't contain red or purple food dyes. Always check with your doctor for specific brand approvals.

Red and purple dyes can stain the lining of your colon, potentially being mistaken for blood or other issues during the colonoscopy and leading to an inaccurate reading or a repeat procedure.

Yes, sodas like Sprite and 7-Up are clear and generally considered safe to drink during the clear liquid diet phase before a colonoscopy.

You should avoid any soda with red, purple, or dark blue coloring, such as grape soda, red punch, or certain sports drinks, to prevent staining the colon.

While many guidelines permit cola and diet cola, as they are considered clear liquids, some specific hospital protocols might exclude root beer. Always check your specific prep sheet.

While soda doesn't contain pulp, it's important to know that for other clear liquids like juice, it must be pulp-free. The clear liquid rule applies to everything, including carbonated beverages.

Soda, particularly regular soda, can provide some calories and energy during the prep, which can help prevent low blood sugar and the shaky feeling that can accompany a clear liquid diet. Chilling the soda can also help make the prep more tolerable.