Cephalexin and Upset Stomach: What Users Say

• The...
• September 8, 2020

For Bacterial Infection "Basically, I got strep throat, and the first several days on cephalexin were fine, except for a bit of a stomach ache. Then, soon after, my body temperature dropped to 94.3, and I got extreme vertigo. Kept having worrying, empty life feelings. Cephalexin works a little too well, not only gets rid of the bacteria, but almost getting rid of the human in the process."

• 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."

• 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."

• Anonymous
• July 22, 2011

Cephalexin for Skin or Soft Tissue Infection "Works very well for treating the cellulitis I got from an insect bite. But don't drink alcohol while you are on this medication. I had half a beer and started feeling really nauseous, had a migraine and my stomach hurt."

• Ama...
• Taken for less than 1 month
• September 14, 2018

Cephalexin for Bladder Infection "I have constant battles with UTIs, so I’ve taken a lot of different antibiotics. Keflex is definitely a good one, but for me, I have to take 500 mg three times a day, so I get some side effects, mostly tired, stomach cramps, and dizzy. It’s not bad, though, like some of the other ones I’ve taken. Before I had repeat infections, I had the 500 mg twice a day dose and had very minor cramping from that dose. It’s my go-to when I can take it. Drink lots of water with it too, it helps flush your system faster and get rid of the infection and its side effects quicker."

• Pes...
• April 20, 2020

For Skin or Soft Tissue Infection "Surprised this old antibiotic drug, cephalexin, still works. I've had good luck with it for my recurrent cellulitis. I had to get a repeat course for my first infection, but that was probably because it was a really bad one (my ankle was the size of an abnormally large grapefruit). Taking it three times a day is a bit of a hassle, and the odor of the medication is foul enough to peel wallpaper, but I would rather deal with these trivial inconveniences than end up on IV antibiotics. I'm able to take this medication with or without food, but taking it without food gave me a stomachache. The good news is that it doesn't take a lot of food to blunt its side effects - a PB&J sandwich or a protein bar is enough."

• She...
• Taken for less than 1 month
• June 24, 2020

For Bacterial Infection "I'm currently on my 5th day of cephalexin 500 mg 4X a day. I have an abscess from shaving with a dull razor and not using shaving gel, that's what I'm thinking anyway. Anyway, this antibiotic is really messing me up. I'm anxious, paranoid around people, super irritable, I feel scared in general. My stomach is distended and I'm constipated and retaining water. I want to stop, but I'm scared to. I'm going to call my doctor. Thanks everyone for posting about your experience. Helping me a lot."

• Tir...
• Taken for less than 1 month
• January 4, 2020

For Bacterial Infection "I had a combination of an infection after an extraction, as well as a skin infection that hurt very badly (both things). I was prescribed 500 mg of cephalexin every 6 hours. By the second day, they were both feeling so much better. I was hesitant because I've had allergic reactions to other antibiotics and a severe reaction to Bactrim. Thankfully, nothing like that with this medication, but it does cause a very inconvenient stomach upset that causes me to have to get to the bathroom in a hurry throughout the day. I have noticed I'm more tired, I'm not sure if that's a side effect from the medication alone or because of having to use the bathroom so often. But I push through the negatives because it has done wonders for the infections."

• Pau...
• Taken for less than 1 month
• August 17, 2018

For Skin or Soft Tissue Infection "Excellent medication for soft tissue infection. Prescribed 500 mg 4x daily for 7 days - noticeable improvement after 24 hours, significant improvement after 48 hours. I'm thrilled. On day one, I did feel some stomach upset, which easily subsided with a bit of food and rest."

• Rob...
• Taken for 6 months to 1 year
• June 13, 2019

For Bone infection "I've been on cephalexin for 5 months for a bone infection, and I have another month to go. I had a hip replacement, which became severely infected about a month later. The side effects of this are horrible. I get dry heaves at least 3 times per day, usually within an hour of taking it. Sour stomach is also another huge side effect. Extreme fatigue is another one. Being on this medicine has destroyed my sleep cycle. I wake up at 2-3 AM as I feel like I have to throw up, or my stomach just hurts. I started with intravenous injections through a PICC line for antibiotics, then it was changed to this green, nasty pill. Because of the sickness that it creates, I have missed almost 6 months of work. I try to get up in the morning, get ready for work, and end up dry heaving into the toilet. Four months into the use of this antibiotic, my hair is starting to fall out as well. This is a nasty medicine, but I do understand why it is needed. I really do not want my hip hardware removed."

• 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."

• Bro...
• March 6, 2018

For Skin or Soft Tissue Infection "I went on cephalexin for the beginning of a staph infection caused by an ingrown hair on my bikini line. I'm currently on day 5 of my 7-day treatment, and my infection is fully healed. Pleasant experience overall; no side effects besides headaches the first 2 days, but minor; pain relievers not needed. However, I didn't consume alcohol or caffeine for the entirety of the treatment as I was advised that cephalexin enhances side effects caused by alcohol and coffee, such as drowsiness, dizziness, upset stomach, etc. I had a chai drink containing a very little amount of caffeine; I got dizzy and very anxious within the hour of drinking it. It never happened to me before despite countless times having the drink, so I related it to the drug, further exemplifying how much the medication enhances both physiological and neurological effects of substances such as caffeine. I recommend this medication, but use with caution: no caffeine or alcohol."

• Gin...
• Taken for less than 1 month
• August 18, 2018

For Skin or Soft Tissue Infection "I was prescribed Cephalexin by a doctor at a hospital I visited when my arm swelled up and the rash I had got very severe. I had been exposed to poison sumac three weeks prior and it just went nuts in that third week. When the swelling entered my hand, I knew I was in trouble. I was prescribed prednisone, which got rid of the swelling splendidly, and Cephalexin to deal with the infection. The Cephalexin dosage was 4 per day for 7 days. It made me overly anxious, I had trouble sleeping, my stomach was a little upset, and I ended up with vaginal discharge (really yucky), but it was so important to get rid of that infection, I took the entire prescription. My arm is in much better shape, though not 100% yet. I am satisfied with the positive results."

• the...
• Taken for less than 1 month
• September 11, 2018

For Bacterial Infection "Was prescribed cephalexin for an infection after a previous antibiotic didn’t work. The infection almost completely cleared up within 24 hours. Worked very well and would definitely recommend. Side effects: sore stomach and dry/bloodshot eyes. Both went away after I finished the course of antibiotics."

• NoT...
• Taken for less than 1 month
• November 11, 2015

For Bacterial Infection "I'm currently halfway through my Keflex treatment for a skin infection on my ankle. I'm prescribed 500 mg twice a day for 30 days. I wish I could be one of the few to say this has been a pleasant experience. I'm not sure if whatever this infection is is just highly resistant or was just that bad, but I'm on week 3 and have only seen mild improvement so far. Plus, this stinky antibiotic is making me miserable... nausea, diarrhea 5 times a day on average, stomach cramps, and joint aches. I've been taking probiotics the entire time I've been on Keflex because I've always had issues with yeast infections even prior to this. I plan on calling the doctor tomorrow to see if I have any alternatives."

• Sto...
• Taken for less than 1 month
• December 10, 2015

For Bacterial Infection "I have an abscess growing in my nose. Basically, it is a pus-filled pimple. Very disgusting to know this is inside my sensitive nose. I was prescribed 500 mg 4 times a day. Within the 4th dose, I noticed the pain in my nose less and less. I am on day 4, and although I feel the occasional tenderness in my nose, the meds are working. But...I feel horrible. I have constant stomach cramps, tightness where it hurts to bend over or reach for something where I use my stomach muscles. I have gas, and I'm bloated. I feel dizzy to the point I occasionally lose balance. So far, I haven't had diarrhea, probably because I tend to be constipated lately due to other issues. I have, though, used the bathroom twice a day, but it is a relief to go."

• Ano...
• Taken for less than 1 month
• November 21, 2019

For Kidney Infections "Went to the ER Sunday for pain in back, constant feeling of needing to pee, pain when urinating, and blood in urine. Diagnosed with a kidney infection and was prescribed 500mg of Keflex 2x a day for 10 days. Since then there isn’t any more blood or pain when I pee. I also don’t have to go every 2 seconds, but it’s day 4 and I’m having some wicked side effects. I am exhausted. I still definitely have the infection (had a follow-up appointment already), so that could be contributing to the tiredness, but I’m falling asleep every 2-3 hours. First 2 days I had terrible diarrhea, but now I’m constipated. The stomach cramps are also really not fun. Taking lots of Advil to help with that. I haven’t been able to work due to these side effects and the symptoms from the infection. But the meds are working, getting rid of one symptom at a time."

• Ada...
• October 31, 2017

For Skin or Soft Tissue Infection "Got 500 mg of Keflex prescribed to me for alleged infected spider bites. Day one, I felt okay, had to go to the bathroom a lot, but otherwise, my stomach wasn't too bad. By night two, I was on the verge of going to the ER. My stomach felt like it was eating itself, my BP/pulse through the roof, every muscle in my body was spasming, and I was in full freak-out mode. Stopped taking it after that. It's been four days since I took it, and I'm still sick. Dizzy, can't eat, feel crappy and weak. Doc said the antibiotics made me sick and that I had to be on the BRAT diet (bananas, rice, applesauce, and toast) for a week. FUN!"

• Har...
• August 21, 2017

For Bladder Infection "This medicine was effective in curing a UTI during pregnancy, but it was also effective at causing upset stomach and vomiting. I am allergic to penicillin and had no allergic reactions to Keflex, but it did cause me to feel very ill by the second pill of the day. I took this medicine 3x a day for 8 days, and by the second day, I knew we would have stomach issues. I took plenty of probiotics, but it's just a very powerful medicine."

• SMc...
• Taken for less than 1 month
• June 26, 2018

For Skin or Soft Tissue Infection "I was on 500 mg four times a day for the week. It was great the first few days until I woke up because my stomach started burning. I had consistent diarrhea the whole day and the next. I also started feeling anxious to the point of a possible panic attack, which I haven’t had in about 3 years. Needless to say, yes, it helped my infection, however, I would rather have it than go through that again. I had to leave work halfway through my shift because of it, so I tossed them in the garbage."

• Ros...
• Taken for less than 1 month
• August 7, 2020

Cephalexin for Bladder Infection "I had cystitis and was put on Macrobid for 5 days, only to find out it didn’t do a thing for the infection. My Dr. gave me an injection of Rocephin in the office and suggested Keflex for 7 days, three times a day (500 mg). The Rocephin gave me a stomach ache and diarrhea, then I took Keflex, and it made me queasy the rest of the day. The second pill I was fine and have remained side effect-free since then. I finish my course tomorrow but still feel the cramping and mild pain from a UTI, so I’m not sure this antibiotic worked either. We’ll see!"

• Rac...
• Taken for less than 1 month
• May 16, 2023

"I have been prescribed 500 mg of Keflex four times a day for 10 days to help clear up a tooth infection that has caused cellulitis on the right side of my face. I was previously on a 14-day course of amoxicillin, but that did nothing. The dentist recommended we now try Keflex. I was apprehensive after reading some of these reviews, but I was also desperate considering the swelling had me looking like Quasimodo. I would love to say that I am having a side effect-free experience with this med, but that is not the case. Within hours of taking my first dose, I experienced stomach pain and bloating. I made sure I took it with a full meal to avoid any nausea or vomiting. The bloating and stomach cramping have continued and have not let up. I’m on day 6 and beyond miserable. I am constipated, bloated, have debilitating stomach pains, and have gained 4 pounds. I’m trying to finish the course, but it’s a struggle. The facial swelling went down by day 4, so that’s a plus."

• Apr...
• Taken for less than 1 month
• March 14, 2024

For Bladder Infection "I started taking Cephalexin after a procedure I had (HSG) left me with a severe UTI and/or bladder infection. I had the severe burning sensation and abdominal pain prior to taking medication within 24 hours. I notice a major difference. I experienced very dark red-orange urine for the next four days of taking this medicine. I thought it was the pills, but by day five and six my urine was no longer red and orange, it was clearer. While on this medicine, I did feel a lot more tired than usual. I spent most of my days in bed, every now and again, I would get a very upset stomach and only had diarrhea one time. I am now on day seven of my medication and no longer experience the dark urine or abdominal pain or upset stomach, the medicine seems to have worked very well, and I am satisfied. One thing I did was drink a lot of water while on this antibiotic. It worked best when I didn’t eat, when I ate, I felt a little more nauseous and lethargic."

• gjp...
• March 1, 2016

For Skin or Soft Tissue Infection "I try not to take medicine unless I am really sick, but my doctor recommended I take cephalexin for a small cyst on my eyelid. I decided to try it because antibiotics are one of the medicines I believe are very good when you are sick and your body needs a little help to heal. My dosage was three 500 mg per day for 10 days. After the first day, I developed stomach cramps and diarrhea. I was not sure if it was due to the medicine, so I continued to take the cephalexin for two more days. When the condition did not get any better, I stopped taking the cephalexin. It has now been a week since I first took the cephalexin, and I still have stomach cramps and diarrhea. I advised my doctor's office of my problem, but they have not called me yet."

• uta...
• Taken for less than 1 month
• July 1, 2016

For Bacterial Endocarditis Prevention "I'm on this for when I get my teeth cleaned at the dentist to protect me from bacterial endocarditis. So far, so good, but I read the bad reviews and the good reviews. I had to bring it down to 8 because I do get a nausea feeling after this, and if I burp, there is a nasty smell from my mouth being open when burping. The main problem I have with this drug is that it makes my stomach hurt, like I am going to throw up. The way I am diabetic and eat at night. I can't eat a big meal each time I take it 3 times a day. So I drink milk, and it helps pretty good with the pain in the stomach. I am only on my second day. Still makes my stomach hurt. I will get some more milk after this review. I am allergic to PCN, and they still gave me this. I looked it up on the internet that it is a substitute for PCN. I hope I am okay after I am done using it."