Answer:
Taking large spectrum antibiotics not only kills the pathogenic organisms in the body but also kills the good microorganisms present in the body. It destroys the gut microflora which can cause antibiotic-associated diarrhea and other digestive problems.
So doctors prefer the patients to consume probiotics to get relieve from diarrhea and digestive problems because probiotics contain live microorganisms that are present in our gut and help us to digest the food.
Fermented foods like curd, buttermilk, pickles, cheese contains a large amount of probiotic cultures like species of Lactobacillus, Leuconosto, Streptococcus, etc which are good for gaining healthy gut microflora and get relieved from antibiotic-associated diarrhea and other digestive problems.
Therefore the doctor will recommend Amanda to take probiotics to relieve her diarrhea and digestive problems.