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Cephalexin and Diarrhea: What Users Say

Brand names: Keflex

Diarrhea: mentioned by 67 users (13.2%)

Based on user experiences from 509 Cephalexin 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.

nausea 14.5%
diarrhea 13.2%
headaches 11.6%
dizziness 8.6%
tiredness 7.7%
anxiety 7.3%
upset stomach 5.9%
fatigue 5.7%
stomach pain 3.7%
pain 3.3%

Reviews for Cephalexin

Commonly mentioned side effects
  • dav...
  • Taken for less than 1 month
  • March 16, 2016

Cephalexin for Skin or Soft Tissue Infection "Had an ingrown toenail infection. Was given 500mg Keflex taken 4 times a day for 7 days. It is working and I have no pain in my toe. However, so far I've had diarrhea, stomach pain, tiredness and weakness, dizzy spells, yellow skin, loss of appetite, nausea, red scratchy eyes. So most of the usual stuff. The long and short of it is my toe will be healed as long as I can deal with the side effects for a few more days."

6 / 10
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90 Report
  • Jea...
  • Taken for less than 1 month
  • May 28, 2019

Cephalexin for Bladder Infection "Took a 500 mg dose of Keflex twice a day for one week - I had a UTI. Side effects were diarrhea, headaches, felt depressed, upset stomach, and nausea. Now I’m having stomach cramping. Just hope the urinary tract infection I had is gone after taking this strong antibiotic."

10 / 10
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52 Report
  • Tes...
  • October 14, 2015

For Bacterial Infection "I was prescribed 500mg of Cephalexin for a staph infection on my face. I took 4 pills a day for 2 weeks. I was surprised to come on this site and find some bad reviews and side effects because my experience with this medication has been phenomenal! My bacterial infection cleared up within days! I had no side effects, and I am not having any problems with diarrhea (though if you do have this problem, you can take something with the pill). The medication definitely smells bad, haha, but I learned that that is completely normal. It doesn't really 'taste' like anything because you just drink it with water and swallow it anyway. I definitely recommend Cephalexin."

10 / 10
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67 Report

Frequently asked questions

  • Anonymous
  • May 14, 2010

For Bladder Infection "Have been taking this medicine for reoccurring UTIs, I take 500mg four times a day for 10 days. I have noticed that people have put mouth pain as a side effect. To be specific, with me, my tongue hurt, which I found out was 'thrush'. Easily taken care of with rinsing mouth out with colloidal silver or you can call your dentist and do what he or she recommends. I have had abdominal pain and diarrhea, however, to relieve me of the UTI, this was well worth it."

7 / 10
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86 Report
  • Lyn...
  • June 8, 2019

For Skin or Soft Tissue Infection "Cephalexin got rid of the infection, but I had horrible side effects. I took it for 4 days, at a dose of 500 mg, 4 times a day. I had horrible headaches, diarrhea, major depression, dry and bloodshot eyes, nausea, was very tired, and didn't have motivation to do anything. Anxiety, joints were on fire! Stopped a day ago and still feel awful! Won't take it again because of side effects."

7 / 10
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33 Report

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  • Ros...
  • September 15, 2013

For Skin or Soft Tissue Infection "I had a small but very painful boil, and the Dr. gave me cephalexin. It worked really well and cleared it within a couple of days, but the side effects were terrible. I had bad gas and cramps along with diarrhea."

5 / 10
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55 Report
  • Tay...
  • December 30, 2015

For Kidney Infections "I got put on cephalexin for an untreated UTI, which obviously spread to my kidneys. I am currently on day 3, and I do feel so much better kidney pain and urinating wise. But it gives me insane diarrhea, makes me feel very nauseous, makes me confused with really bad anxiety, and gives me killer heartburn. I am currently on 500 mg, 4 times a day."

4 / 10
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40 Report

More FAQ

  • Ali...
  • May 12, 2016

For Bladder Infection "I took cephalexin 500 for ten days following a 5-day stay at my local hospital (with IV antibiotics) for a bladder infection. It did nothing for my infection. But I did get a few nasty side effects: diarrhea, nightmares, and muscle pain. This medication did not work for me."

1 / 10
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37 Report
  • Tes...
  • Taken for less than 1 month
  • July 8, 2019

Cephalexin for Acne "I started taking this medication initially for an infection from a bug bite. After three days of being on the medication, I noticed all of my skin is clear and appears to be glowing, and my pores have shrunk so much. I’m in my early 30s and still suffer from acne occasionally, mostly hormonal acne, and this is amazing. I don’t want to get off of it now. I was on doxycycline for months in my early 20s, which also had a similar effect. The only side effects from this medication initially were a headache and diarrhea, but that went away after one day, and I’m staying on probiotics to help regulate."

10 / 10
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22 Report
  • sic...
  • August 4, 2015

For Bacterial Infection "I took it for ten days for a skin infection. Cleared it up in ten days. Despite taking so many probiotics and eating yogurt, I got severe diarrhea, and I STILL have mild diarrhea. Also, if you're a woman, be prepared for a yeast infection. It's driving me insane."

8 / 10
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31 Report
  • Sme...
  • June 24, 2016

For Bladder Infection "I have been on these antibiotics for 5 days now and so far so good in clearing the infection of cystitis. I am no longer in agony, however, I started getting diarrhea straight away, which has lasted so far the 5 days. Rumbling in my stomach and also then very bad wind and burping, which smells very much like eggs. Not the best side effect for anyone around."

7 / 10
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34 Report
  • APR...
  • Taken for less than 1 month
  • August 15, 2019

For Bladder Infection "The cephalexin drug worked slowly for my bladder infection, taking the whole 72 hours they recommend to wait to see if it works. But it got rid of the infection. Side effects were bloating, diarrhea, depression, slight cough, and increased heart rate. Side effects were a pain, but overall better than an infection."

8 / 10
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20 Report
  • Aly...
  • Taken for less than 1 month
  • April 30, 2018

For Skin or Soft Tissue Infection "Ended up with an infected wound after foot surgery. Was leaking pus and blood from the incision site. Was put on 500 mg 2x a day for 10 days. After the 3rd day, I noticed no more pus, just blood draining. The pain decreased as well. No bad reaction as I usually get very nauseous from other antibiotics, but not Keflex. I made sure to take the dose on time every day and had a small meal 10 minutes before each dose. 2 hours after each dose, I took a double dose of probiotics and was also taking Saccharomyces boulardii (another probiotic, but it is a yeast and is not killed by antibiotics since it is not a bacteria). Did NOT experience any stomach pains, diarrhea, anxiety, lightheadedness like others. Also stopped drinking coffee and consuming sugar while on these antibiotics, bacteria thrive on sugar in the gut, and the coffee makes your body acidic."

9 / 10
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22 Report
  • Lad...
  • Taken for less than 1 month
  • December 27, 2012

For Skin or Soft Tissue Infection "Had a bad reaction all the way. Within 15 minutes of taking, experienced shortness of breath, dizziness, diarrhea, throwing up, shakiness, full-blown rash/hives, cold/chills, confusion, slurred speech, rapid heart rate, ringing in the ears, extreme tiredness."

1 / 10
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44 Report
  • Buf...
  • April 30, 2016

For Skin or Soft Tissue Infection "I've been fighting cellulitis in both legs for 2 years! After 2 hospital stays and several different doctors, my newest put me on 500 mg 4 times daily. After only 3 days, my legs look and feel better than they have since I first got it! Also, I've been taking 5 or 10 mg of oxycodone every 6 hours to ease the pain. I took 0 the last 24 hours! The only side effect is diarrhea, which is a pleasure after being constantly constipated from the oxy!"

10 / 10
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27 Report
  • Jad...
  • February 18, 2017

For Skin or Soft Tissue Infection "This drug has worked very well! I had a skin infection, with a urinary tract infection. I was put on the medicine for 10 days, 2 times a day. The first couple of doses, I didn't think that it was really working, but after 4 days of taking the medicine, then bumps started to go away, and I could urinate comfortably without any burning. On the 8th day, the bumps have completely dried up, and new skin is forming on top. I didn't really experience any bad side effects. The only side effects I had were minor diarrhea and fatigue. I would definitely recommend this medicine. My only wish would be that it would do a better job at clearing the bumps more effectively!"

9 / 10
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23 Report
  • Anonymous
  • January 25, 2020

For Bacterial Infection "Okay, so I recently had the ovarian removal of my left ovary at the beginning of the month. Fast forward about three weeks, and I see that my belly button, which was one of the areas they went in through, had a pool of pus in it (even though I had no fever, nor did I really have any redness or swelling). But I thought it would be better to be safe than sorry, so I went to the ER. The doctor barely looked it over, acted like he didn't even want to be there, and then sent his nurse in to prescribe me this garbage antibiotic, cephalexin. I am going on day four, and I'm done. There's no way I can continue this medication for 7 days. It in a short amount of time has already made me incredibly dizzy and fatigued, but has given me horrible stomach aches that come and go, diarrhea, and a feeling like I'm about to faint. It looks like the infection is gone, and if it's not, then I will go to my primary care doctor and have them prescribe me something else."

1 / 10
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20 Report
  • Inf...
  • Taken for less than 1 month
  • April 16, 2017

For Skin or Soft Tissue Infection "I had a blister get infected on a cruise ship. The onboard doctor put me on cephalexin 4x daily at 500 mg for 5 days. I've had insomnia from the get-go. While awake, I had dizzy spells often and bursts of anxiety. On night 3, I developed chills and anxiety that woke me right up. I then vomited and had diarrhea all night long. I'm currently awake on night 3 typing this. Chills have stopped, but I'm holding nothing down."

7 / 10
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23 Report
  • jes...
  • November 23, 2020

Cephalexin for Upper Respiratory Tract Infection "I went to the ER, they said I had a UTI, so they gave me Keflex 500 mg 4 times a day for a week. I despise ANY medication because of the side effects, but I didn’t want a kidney infection as that’s way worse, so I took it. I had nausea and some mild diarrhea about an hour in, normal, right? So, a few days in, I felt like I was hit by a truck. I woke up fatigued, my anxiety was so bad, and I developed an achy back that lasted a week even after I was done taking it! I still have some mild diarrhea every day, and it’s been a week since I’ve finished the medicine. I have no clue how I pulled through and took all of it. It did indeed clear up my infection, but I still feel sick. I know it’s a turn-off reading this, and it makes you not want to take the medicine, but you HAVE TO unless you want a kidney infection, which is way worse, and you’ll be put on even more antibiotics if that happens. Just pull on through, but if you genuinely don’t feel good when taking it, talk to your doctor."

5 / 10
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13 Report
  • Chr...
  • Taken for less than 1 month
  • November 23, 2019

For Skin or Soft Tissue Infection "I was given this antibiotic, cephalexin, for a stab wound accidentally self-inflicted. I feel horrible. I have low to no energy. I'm sitting in the bathroom with diarrhea and nausea. This is my first day on it. I do think I can tolerate it."

2 / 10
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15 Report
  • Anonymous
  • May 2, 2016

For Skin or Soft Tissue Infection "I had a fungal toenail infection, went to the doctor, prescribed Cephalexin 500 mg cap 2 twice daily. As I have IBS, took it with food to not upset my stomach, 1st 2, no effect, but when I took the next two, thought I was going to die. I woke up at 2 am with severe stomach pain, nausea, dizziness. I was draped over the bathroom counter, thought I was going to pass out. Within 10 mins, my hair was soaking wet and had perspiration running down my face and having diarrhea at the same time. I live alone, 73, was considering calling 911. The next 2 mornings, I saw that my gums had been bleeding, not red but dark purplish-black. As I have dentures, it was inside and between my teeth. Found it can cause gum bleeding. Talked to the pharmacy, said to stop it. Never again."

1 / 10
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24 Report
  • Anonymous
  • Taken for less than 1 month
  • April 26, 2022

For Bladder Infection "This drug was prescribed for a bladder infection by a new doctor, after my family doctor retired. I didn't realize it, but this was the same drug that my dentist had prescribed the week before for a tooth infection and made me ill. Different doctors, different drug stores, but the same drug. After taking one dose of 500 mg, I became violently ill, vomiting 28 times over several hours. I also had diarrhea at the same time. I don't think I've ever been so sick. I am 92 years old and have been sick before, but not like this. I was so weak, I had difficulty lifting myself off the floor to get to the toilet for the next round. I was really thinking I would die. I don't mean to scare anyone, and evidently, most on here have had good results, but just know that it's possible to be ill from this stuff. And be careful to read labels and compare similar dosages from different doctors."

1 / 10
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8 Report
  • Nev...
  • Taken for less than 1 month
  • August 12, 2018

For Skin or Soft Tissue Infection "I was prescribed Cephalexin 500 mg 3X a day for 10 days. From the first day, I had stomach pain, diarrhea, headache, anxiety, confusion, and heart palpitations. At first, I thought all of these issues were from being sick and lack of sleep. By day two, I knew it was this medicine. I went down to two doses a day, but by day 5, I had to stop taking it. Worst drug ever! The smell of the drug is a cross between a rotting dead animal and rotten eggs, never again will I touch this drug. Usually, I read drug info before starting a drug, but I was so sick I failed to do this first. Going forward, I will not make this mistake. I experienced too many side effects from this drug."

1 / 10
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19 Report
  • Ash...
  • August 6, 2014

For Skin or Soft Tissue Infection "Was given 500 mg 3 x daily for 10 days for pimple-like rash bumps all over body and for a bladder infection. Today is my first day, already experiencing ringing in ears, diarrhea, blurry vision, and a headache. Not too thrilled, I guess I'll have to play this out carefully."

4 / 10
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28 Report
  • Poo...
  • December 22, 2017

For Bacterial Infection "I am currently on cephalexin 500mg × 4 times a day for my strep throat and UTI. It has completely taken my appetite, so I now have to force myself to eat. My stomach hurts so bad, severe headaches, diarrhea, and hot and cold flashes, and all I want to do is sleep all day. I'm only on day four and have 3 more to go if I can make it."

5 / 10
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17 Report

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Reviews may be edited to correct grammar/spelling or remove inappropriate content. Reviews appearing to come from parties with a vested interest are not published. This information is not intended to endorse any medication and should not replace the expertise and judgment of healthcare professionals.