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MiraLAX and Diarrhea: What Users Say

Diarrhea: mentioned by 17 users (6.5%)

Based on user experiences from 262 MiraLAX reviews, the following table shows the most commonly mentioned side effects.

All user comments are moderated by Drugs.com. Each review is verified for relevance and screened for inappropriate content. Side effects are user-reported and not clinically verified.

bloating 11.1%
nausea 10.7%
cramps 9.5%
gas 9.5%
constipation 6.9%
diarrhea 6.5%
pain 6.1%
vomiting 5.0%
upset stomach 4.2%
stomach pain 1.9%

Reviews for MiraLAX

Commonly mentioned side effects
  • Kit...
  • Taken for 6 months to 1 year
  • October 24, 2019

For Constipation "I have had IBS since I was about 7 years old. Back then, there was no such thing as IBS. Finally, at age 15, I was told I have IBS. Back then, I got severe constipation, then severe diarrhea with such bad cramping! Then at age 20, it just turned to just constipation. So from the age of 20 till last year, I only went 2 times a week. I could not take anything due to the cramping. Then I found Milk of Magnesia, which did work, but I had to get the right dose, usually the child dose. About 8 months ago, I got so constipated! I always thought Miralax was harsh. So, since I had not gone in almost 2 weeks, I would try anything! I took it for 2 days, then I had the best bowel movement I can remember! Now I take it about 1 time a week, with NO cramping and NO diarrhea. From age 20 to my current age, I had only had those round balls of stool. Now when I go, it is sausage-like - how it is supposed to be! To be honest, I just can't believe how large and long my stools are! Have a great day everyone! You have got to try this!"

10 / 10
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232 Report
  • not...
  • Taken for less than 1 month
  • June 29, 2021

For Bowel Preparation "Was prescribed Miralax & Dulcolax combination for colonoscopy prep. I was in tears, hyperventilating from the horror story reviews in this forum. I came here to say: IT IS NOT THAT BAD. I’m 23 years old and (still) have a horrible fear of vomiting. I was petrified to take the doses prescribed because of some of these reviews. I forced myself to do it for the sake of getting this thing over with. Took 4 Dulcolax at 4 pm along with an anti-nausea medicine, followed by the Miralax solution starting at 5 pm. A couple of normal bowel movements within the first hour, then water-like bowel movements every 20-30 mins until about 11 pm/midnight. No pain, no vomiting, no nausea. Just diarrhea as intended. You’ll be a little chilly but NOTHING unbearable. You got it."

9 / 10
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72 Report
  • Fai...
  • Taken for 2 to 5 years
  • June 30, 2019

For Constipation "Love MiraLAX! After my first semester of dining hall food in college, I was messed up BAD. I had to start using laxatives for relief, and they really bloated me out. My doctor recommended MiraLAX, and the rest is history. I’ve never been regular, but as long as I drink enough water, I have no problem getting a bowel movement with this! That’s also something my doctor said... STAY HYDRATED. MiraLAX is an osmotic-type laxative and really only works if you are drinking enough liquids! It takes one dose at night for me to have a movement around lunch the next day! If I haven’t been drinking a lot, then it usually takes 3-4 days of continual use for me to get a movement... and those are always loose. Otherwise, they are easy to pass and healthy quality."

9 / 10
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60 Report

Frequently asked questions

  • Anonymous
  • April 12, 2011

For Constipation "This medication is heaven sent! We suffer from bad constipation in my family. We eat healthy and a very high-fiber diet, get plenty of exercise, and drink lots of water, and still get constipated. MiraLAX is our solution for this problem, it is even gentle enough for my kids. I do not recommend taking it daily because you could get very loose stools. You could take it two days in a row to empty out and then switch to every other day or even every two days. This works for me and I have really bad constipation."

10 / 10
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103 Report
  • Gin...
  • Taken for 1 to 2 years
  • August 14, 2018

For Constipation "I have had normal bowel movements most of my life. Then I turned 29, and it started slowing down dramatically. Genetically, my father had gastrointestinal issues such as IBS, and he had food sensitivities. I am now learning all about this and had been suffering for 2 years with constipation. Stool softeners were so harsh on my stomach, but I took them because they worked. Metamucil wasn't effective for me and still left me with bad constipation, as well as laxatives, salines, and suppositories. My gastroenterologist recommended MiraLAX, and I initially had to wait almost 3 days. Then it was diarrhea because I was so backed up. So now I have a happy medium. The amount I take every day that gives me relief, comfort, and regularity. I go anywhere from 2 to 4 times a day, soft to semi-loose stools. I couldn't be happier and healthier, I recommend trying this ASAP!"

10 / 10
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39 Report

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  • She...
  • Taken for less than 1 month
  • May 20, 2018

For Constipation "I've suffered from constipation most of my life, using different laxatives such as senna, Dulcolax, milk of magnesia, suppositories, and enemas. They worked, but they would also give me very loose stools and/or horrible stomach cramping. I was having another bad bout of constipation, alternating 3 days before I would have a BM. Decided to give MiraLAX a try after my brother, who also had chronic constipation, recommended it to me. I took it after a meal before bedtime, and I noticed my stomach was gurgling but no real discomfort, I think I could feel the stuff moving everything through the colon. Woke up this morning, and after drinking some more water, I was able to finally have a bowel movement that was firm yet soft and not watery whatsoever. Finally, relief! I'd also like to note that I usually strain really hard to have a BM, but with MiraLAX, all I had to do was relax, and it came right out. Would definitely recommend!"

10 / 10
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38 Report
  • Ano...
  • Taken for less than 1 month
  • June 25, 2020

For Bowel Preparation "I tried the MiraLAX colonoscopy prep about 3 weeks ago because I didn't want to have to drink the traditional prep, and it sounded less awful. BIG mistake. I did exactly as I was supposed to, liquid diet, etc., and this made me so sick, I was up with diarrhea and vomiting all night. Not only that, my 8:30 am colonoscopy had to be canceled because I was nowhere near clear, even though I had taken all of it per instructions. It has taken me 3 weeks for my bowels to become normal again, and I'm getting ready to do a 'make-up' colonoscopy using the traditional yucky drink. At least the yuck will work. MiraLAX as an occasional laxative is fine, but never for colonoscopy prep, at least not for me."

3 / 10
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30 Report

More FAQ

  • Cry...
  • Taken for less than 1 month
  • May 15, 2019

For Constipation "I’ve been constipated for the last 5 years after 2 major surgeries on my brain/spine due to brain cancer, which left me paralyzed. My dr finally prescribed MiraLAX after other laxatives were not working. I’m really hoping this works, as at the moment I only have a bowel movement once every 1-2 weeks. As of today, it’s actually been 3 weeks and 2 days since I’ve had a BM. Just took this medication an hour ago, and I already have diarrhea. I hope this doesn’t last long. I just want a normal BM for once."

8 / 10
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27 Report
  • Joe...
  • October 3, 2020

For Bowel Preparation "I am a 190 lb man and took the MiraLAX/Gatorade bowel prep (Dulcolax and Gas-X, then 8 oz MiraLAX in 64 oz Gatorade, drink for 2 hours) starting at 6:00 AM following a day of liquid diet. By 9:00 AM, I had one normal bowel movement and one loose movement. I drank more water, felt bloated and nauseous, but by 10:45, I had no more bowel movements. I used a Fleet enema and stopped drinking because I was not allowed to drink any more 3 hours before my 1:00 PM colonoscopy. My colonoscopy was aborted midway due to inadequate prep. It is now 4 days later, and I still have diarrhea. I do not recommend this for a bowel prep."

1 / 10
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22 Report
  • roc...
  • Taken for 1 to 6 months
  • September 8, 2024

For Constipation "You want to poop? This will make you poop. I don't promise you'll like the consistency, but you'll definitely poop. You can adjust your dosage to make your stool less soft, surely. Just taking half the recommended dosage, I went from barely pooping once a day to three large movements. I really only require about 1/4 of the recommended dosage to get the job done. Try it if you're constipated!"

10 / 10
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4 Report
  • Unh...
  • Taken for less than 1 month
  • May 5, 2019

For Constipation "Took this after surgery to prevent complications with stitches in the abdominal cavity. After 3 days of using correctly, I can’t sleep and have waterfalls of diarrhea that won’t go away after 2 days off. Sure, it evacuated the system well and crushes destroys everything in its path."

1 / 10
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23 Report
  • DJa...
  • Taken for 6 months to 1 year
  • March 31, 2019

For Constipation "Due to medical problems, I take a lot of different medications and iron on top of them that cause me to become constantly constipated. Miralax works very efficiently on me for the constipation. It takes about a half hour after consuming to produce results. It’s really nice knowing I’ll get quick relief consistently. Rarely does it cause diarrhea for me."

10 / 10
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19 Report
  • DCi...
  • Taken for 1 to 2 years
  • June 2, 2023

For Constipation "I had ongoing constipation as a side effect of my antidepressant (Vortioxetine), and none of the usual treatments were working effectively-e.g., upping fiber intake, pear juice, Citrucel, etc. I started taking MiraLAX, and it worked amazingly well. I'm down to only a fraction of the standard size dose once a day, right before bedtime, but it's enough to keep things moving! I mix it with water and a little Gatorade to make it taste a little less bland. The only caution I have is to not take it if you've had a high-fiber meal (lentils or beans for me) because your stools will be way too loose."

10 / 10
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  • CMW...
  • Taken for less than 1 month
  • December 12, 2021

For Bowel Preparation "I have a colonoscopy every five years. This time my doctor told me to get Dulcolax and MiraLAX as the bowel prep. Their instructions were to take four Dulcolax at noon and then four hours later to start taking the MiraLAX. They said to mix the MiraLAX with two quarts of clear liquid. I chose sugar-free Sprite. No instructions were given as to how much to drink at a time. At first, nothing happened, then about two hours later, I had horrible stomach pains and severe diarrhea that continued through the night. At no time was it ever clear fluid. I went to the clinic the next day at ten but was concerned. Before the procedure, my doctor asked me how I liked the MiraLAX, which was unusual because he has never asked me this before. I told him it was not as effective as previous preps. Evidently, this became pretty evident during the procedure because he noted on my chart that it wasn't. I had diarrhea for three days afterward. Never again."

1 / 10
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7 Report
  • Cle...
  • July 30, 2021

For Constipation, Acute "I’m a healthy 24-year-old female. Usually very regular. But after a recent round of antibiotics, I was suddenly constipated for about 9 days. I tried everything: Metamucil, prune juice, Dulcolax. I finally decided to try MiraLAX. The first time I took a capful, the recommended dosage, it did nothing. Then a couple of days later, I upped the dosage. I poured half the bottle into about 8 oz of prune juice and chugged it. I didn’t feel anything until 3 1/2 hours later (around 10:30 pm). When I tell y’all BUBBLE. GUTS. The most sudden and abrupt bout of gas, gurgling, cramping, and farting. I felt like I was going to poop my pants. I ran to the bathroom. Everything in my stomach was melted and pouring out of me. Not all liquid, just very, very soft stool coming out in a steady stream. For the rest of the night and into today (it’s 3 pm), I’m battling diarrhea. It’s not as bad now, and the cramping has stopped. But I feel so much lighter and relieved."

9 / 10
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6 Report
  • Con...
  • Taken for less than 1 month
  • November 16, 2021

For Constipation "Do NOT use this product if you’re constipated. It only made me poop every 4 days… maybe it was because the medicine I was on caused constipation (I was getting off on it often)! Never gave me explosive diarrhea like I needed. Literally only pooped the smallest amount and I was taking the highest dose I could once a day for like a week and a half."

3 / 10
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2 Report
  • Hoo...
  • March 28, 2017

For Constipation "Loose bowels all the time, my stool smells horrible all."

5 / 10
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18 Report

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