I would definitely not use fresh garlic when afflicted with diarrhea. Yes, it is a natural antibiotic but just as strong an irritant. Pau d' Arco (capsules or tea) is very mild, yet has at least the same antibiotic potency as garlic.
If you have access to yellow mung beans, cooking them together with white Bhasmati rice for at least 45 minutes in soup form with cumin, tumeric, coriander and cardamon, some unsalted butter and unrefined seasalt is good for that kind of intestinal problem. It is called kitchari and is given to people with weakened digestion and diarrhea. It heals the intestinal lining.
Drink ionised water to help the body dispose of undesirable waste matter and toxins (see recipe in The Amazing Liver Cleanse).
If the problem continues, a stool analysis may be advisable. Millions of Americans are affected by Salmonella poisoning or other parasitic infections through food each year. I hope for you that this is not the case.