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Dr. Andrew Rynne

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Took antibiotic for diarrhea. Noticed change in stool color. Is this normal?

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General & Family Physician
Practicing since : 2008
Answered : 3637 Questions
I had a case of severe diarrhea around Nov'12 end. Once diarrhea improved, it was followed by black and messy stools. I took a course (5 days) of antibiotics(Mahcef Plus) along with a medicine called Velgut after consultation with our physician. After the antibiotics course, my stool color has now changed to yellow to light brown but I am still having soft and mushy stools from then. Doctor prescribed my Providac for a period of 5 days inbetween. Stools were ok for that duration. But got back to very soft (like cow dung), once I discontinued Providac.
Have no other issue like abdomen pain etc.
My other parameters
Age: 33 years
Any other symptom or past history: No
Stool Frequency: Once to twice a day
Stool Color: Yellow/Dark Yellow/Maybe Borwnish
Stool formation Very soft very mushy
I had a stool test in between and everything was Ok
I am under a fair bit of stress though in last few days and that is not helping either.
One more point. I had alcohol on new year's eve and after that my stools were black and tarry for a day
Is it normal or what else should I do
Please advise.
Mon, 4 Feb 2013 in Digestion and Bowels
Answered by Dr. Raju A.T 29 minutes later

Thanks for your query.

The diarrhea you had could be due to infection. The fact that you got better after a course of antibiotic confirms my suspicion. Occasionally gastric bleeding secondary to infection or pre-existing gastric ulcer can impair a dark tarry color to the stools.

In the due course of infection and sometimes following antibiotic therapy, some of the essential normal bacteria of the intestines get washed away. The results are reduced absorption of bile salts and other nutrients. This may lead to abnormal stool formation, changes in stool colour and increased motility. Therefore your current symptoms could be the effects of recent infection / antibiotic therapy.

Do not be concerned though, providac and velgut are drugs that solve such problems. It contains spores of lactobacillus acidophilus and other a bacteria essential for normal digestion. Since you had been on Providac for 5 days the problem will surely get corrected, except that sometimes it may take time to become normal. Do wait for a week from now. I expect you to be become normal soon. You may take another course of Providac for some more days for additional benefits.

Besides this stress and physical strains also affect motility of intestines. Adequate destressing by means of adequate sleep, regular food, physical exercise, yoga and transcendental meditation has positive influence on bowel movements.

In the interim monitor the progress. Drink enough fluids and take plenty of fibre XXXXXXX fruits and vegetables. Watch out for persisting dark tarry stools. You should consider getting back to your doctor if needed.

Hope I answered your query.

Please let me know if there are any other concerns.

Above answer was peer-reviewed by
Follow-up: Took antibiotic for diarrhea. Noticed change in stool color. Is this normal? 1 hour later
Thanks doctor for your response. It is encouraging.

Providac twice a day often makes my stools smells very bad and also a bit greasy.Is it expected. What do you think is the ideal dose for providac for me?

This problem has been there for almost 2 months. Do you think it is normal ?
Do you think fruits like banana , XXXXXXX would help?
Please advise
Answered by Dr. Raju A.T 43 minutes later

1. Yes, foul smelling stools can be expected with Providac. Do wait for a week from now to start another course of Providac. You can follow the same dosage and course as advised by your treating doctor before.

2. Yes, sometimes the intestinal upset due to such problems could run for weeks to months.

3. You can take fibre XXXXXXX foods like XXXXXXX Psyllium husk, etc. These form bulk of stool and help in easy evacuation.

Hope this suffices. I will be glad to assist you should you have more concerns.
If all your queries are answered, please close this discussion. I would appreciate your reviews about this service.

Wish you good health.

Above answer was peer-reviewed by
Follow-up: Took antibiotic for diarrhea. Noticed change in stool color. Is this normal? 26 minutes later
Thanks Doc...

One last query. I am also having some bad taste in my mouth. Is it Ok.
Thanks in advance.
Answered by Dr. Raju A.T 4 hours later
Hi again,

Twice a day teeth brushing and mouth wash with antiseptic solution like CHLORHEXIDINE twice daily after food will surely help you to get rid of the bad smell in the mouth.

Wish you good health.

Above answer was peer-reviewed by
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