How Much Miralax Do I Drink Before A Colonoscopy? | Prep Made Simple

You booked the test. Now you need a clean colon and a simple plan. This guide explains the standard MiraLAX plus clear-liquid method many clinics use, when to start drinking, how fast to sip, and when to stop liquids so anesthesia stays safe.

Drinking Miralax Before A Colonoscopy: Exact Amounts And Timing

Most adults mix one full 238 g bottle of Miralax (polyethylene glycol 3350) into 64 oz of a clear drink. The mix becomes a mild, non-salty solution. Chill it. Use a straw if taste bugs you. The plan below fits many morning and afternoon procedures, yet always follow the written plan from your own GI team.

Table 1: Miralax Prep Schedule At A Glance

Step	What To Do	Notes
Supplies	238 g Miralax, 64 oz clear drink, 2 bisacodyl 5 mg tablets if instructed	Avoid red or purple liquids
Mix	Empty the 238 g bottle into the 64 oz drink, cap, and shake until dissolved	Sports drink, clear juice without pulp, or oral rehydration drink all work
Diet Day Before	Switch to clear liquids for the whole day	No solid food
Start Time	Begin the first 32 oz in the late afternoon or early evening	Common window is 5–7 p.m.
Pace	Drink 8 oz every 10–15 minutes until 32 oz are gone	Slow to every 20–30 minutes if you feel queasy
Second Dose	Start the remaining 32 oz 4–6 hours before the scope time	Finish 2–3 hours before arrival
Cutoff For Liquids	Stop all liquids 2 hours before you check in unless your anesthesiologist gave different rules	Water counts as a liquid
Med Add-Ons	Take bisacodyl only if your doctor included it	Some centers add simethicone for less foam

How Much Miralax Do I Drink Before A Colonoscopy?

For the classic over-the-counter plan, the total Miralax amount is 238 g mixed in 64 oz of clear liquid. You do not add more powder beyond this bottle unless your GI team told you to do so. The split dose means you drink 32 oz the evening before and 32 oz on the day of the exam.

Why Split Dosing Works

Split dosing clears the right side of the colon better and helps more polyps get seen. It also leads to less bloating on the day of the scope, since the second dose is closer to the start time. Evidence and society guidance back this approach. See ASGE split-dose guidance for the rationale and data behind this timing method.

What To Mix Miralax With

Pick a clear drink you can tolerate: a sports drink, clear apple juice, white grape juice, oral rehydration drink, clear lemon-lime soda that has gone flat, or water with a flavor packet. Choose sugar-free sports drink if you have diabetes and manage with a low-sugar plan. Skip anything red or purple since it can stain the colon.

Timing Rules For Morning Vs Afternoon Procedures

Morning Start Time

• First dose: 32 oz the prior evening.
• Second dose: start 4–6 hours before your scope time.
• Finish line: complete the dose 2–3 hours before arrival and stop all liquids 2 hours before check-in.

Afternoon Start Time

• First dose: you can drink 32 oz later at night.
• Second dose: a same-day second dose works well. Start 5–6 hours before the scope.
• Finish line: keep the same 2–3 hour finish target for the dose and the 2 hour liquid cutoff. A split-dose regimen like this appears across joint ACG/AGA/ASGE guidance for bowel prep quality.

Hydration Tips That Make The Night Easier

• Keep a second clear drink on the side to sip between cups of prep.
• Add a slice of lemon to your cup, then toss it out after each pour.
• Use a chaser of a different clear drink sometimes to reset the taste.
• If you feel chilled, drink part of the mix at room temp.
• Skin barrier cream helps with soreness. Pat, don’t rub.

Clear Liquids You Can Drink The Day Before

• Water, sparkling or still
• Sports drinks that are not red or purple
• Apple juice, white grape juice
• Plain tea or coffee without creamer
• Clear broth or bouillon
• Lemon-lime soda with the bubbles stirred out
• Popsicles that are not red or purple
• Gelatin desserts that are not red or purple

Common Add-Ons And Medicines

Many centers pair the prep with two 5 mg bisacodyl tablets. Timing varies by clinic. A common plan uses the tablets in the late afternoon before the first dose, or six hours before start time on the day of the scope. Your GI team may add simethicone tablets to cut bubbles. Ask your doctor how to handle blood thinners, GLP-1 injectables, and diabetes meds. Never stop a heart or seizure drug without a written plan from your prescriber.

Safety Notes Before You Start

Use this Miralax plus clear-liquid plan only if your endoscopy team gave you this exact plan. People with kidney disease, heart failure, a history of bowel blockage, or severe constipation need a tailored plan from their own clinician. If you vomit and cannot keep liquids down, or your stool does not turn to clear yellow near the end of the second dose, call the on-call number on your paperwork.

Table 2: Troubleshooting During Prep

Problem	What To Try	When To Call
Nausea or cramps	Pause for 20–30 minutes, walk around, then sip slower	Vomiting more than once or unable to keep liquids down
No bowel movement after first 16–24 oz	Keep sipping at the same pace; gentle walking helps	No response after finishing the first 32 oz
Chills or feeling washed out	Alternate the prep with warm clear broth	Dizziness that does not pass with rest
Sore bottom	Use barrier cream, soft wipes, and a short lukewarm shower	Bleeding more than a streak
Still brown liquid near the end	Finish the second dose; add extra clear liquids if allowed	Brown output one hour before you must leave
Procedure is early and you are behind	Shorten the gap between cups to every 10 minutes	You cannot meet the 2–3 hour finish target

Taste Hacks People Swear By

• Chill the mix for at least two hours.
• Drink through a straw aimed at the back of the tongue.
• Suck on a lemon drop between cups, then spit it out.
• Rinse your mouth with water after each cup.
• Switch between two clear drinks to fight taste fatigue.

What To Expect In The Bathroom

After the first few cups you may pass liquid stool. It turns from brown to tea-colored, then to pale yellow. Near the finish you should see light yellow, nearly clear liquid. Gas and gurgling are common. Most people sleep in short stretches; set phone alarms so you do not miss the second dose window.

When The Plan Differs From Bottle Directions

MiraLAX is approved by the FDA as a laxative for short-term constipation in adults. The colonoscopy prep method described here is an off-label use that many GI groups endorse because the volume and timing clear the colon well. Your exact plan can differ by center and by medical history.

Step-By-Step Checklist You Can Print

1. Seven days out: skip iron and fiber pills.
2. Five days out: switch to lower fiber food, then clear liquids only on the day before.
3. Morning of the day before: buy supplies and chill the mix.
4. Late afternoon or early evening: take bisacodyl only if your GI team told you to do so.
5. Evening before: drink 32 oz, 8 oz every 10–15 minutes. Slow the pace if queasy.
6. Day of procedure: start the second 32 oz 4–6 hours before the scope time.
7. Finish line: complete the dose 2–3 hours before arrival; stop all liquids 2 hours before check-in.
8. Bring a list of your meds and rideshare or a driver.
9. After the scope: start with light food once fully awake unless your doctor says otherwise.

Plain Answers To Common “How Much” Questions

• Can I drink more than 64 oz? Only if your GI team told you to do so.
• Can I split the first 32 oz across the day? No. Drink it in one focused session.
• Can I use water instead of a sports drink? Yes, though many feel better with electrolytes.
• Can I cut the dose if I am small? No. Dose changes come only from your GI team.
• Do I still need the second dose if my output looks clear? Yes. Finish the plan unless told to stop.

Keyword Use And Variations

You asked, “how much miralax do i drink before a colonoscopy?” That exact phrase appears above because readers search that way. This guide also answers “how much miralax do i drink before a colonoscopy?” with clear amounts, timing, and cutoffs. You will also see close variants across the guide so the intent stays clear without odd repetition. Search bots are not the goal; a clean prep and a smooth test are.

Final Nudge

Set timers, stay near a bathroom, and keep sipping. You’re doing real work that pays off with a quality exam and fewer repeat visits.