If the diarrhea is due to an infection by a virus, it will need to run its course.
You can help things along by taking a probiotic (healthy bacteria such as lactobacillus species) daily until better. Diarrhea due to bacterial infections sometimes require antibiotic therapy. Diarrhea that persists more than 2 weeks, or bloody diarrhea of any duration, should be evaluated by your doctor.
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