Hi Thanks for choosing HCM for your query. Most of the antibiotics especially that are given by mouth are associated with diarrhea. In our intestines we have normal bacterial gut flora which are harmless beside there is small group of pathogenic bacteria which are controlled by normal gut flora. Use of antibiotics alter this balance, resulting in the pathogenic bacteria to cause diarrhea. Another reason is some antibiotics have limited spectrum of killing the bacteria, while suppressing the growth or killing the bacteria, the other bacteria are not affected responsible for diarrhea. The antibiotic associated diarrhea can be controlled by using probiotics like Sporolac powder which contains Lactobacillus bacteria which are useful in controlling the balance in our intestines. Hope your query has been explained. give your feedback if convinced.