take an antifungal with the antibiotic. for example, you could ask your doctor for a prescription of nystatin to take during the course of your antibiotic. many dermatologists do this when prescribing long-term antibiotic courses for acne. i suggest adults take two tablets twice a day -- 1 cc of suspension twice a day for children -- to prevent yeast overgrowth in your intestines. most cases of upset stomach or diarrhea that kick in a few days of beginning a round of antibiotics can be cured with a single dose of the drug. diarrhea after a two-week round of antibiotics is likely caused by a different bug altogether -- be sure to bring that to your doctor's attention. i should tell you that, in my clinical practice years, many of my patients made great strides against acne through taking nystatin and a change in diet alone, without the antibiotics.