An August 20, 2019 report by Harvard University cautions the use of probiotic supplements, since they are not categorized as a drug by the FDA and do not undergo the same monitoring. The most common species of bacteria used in probiotics (among a potential 3,000 or so) are species of Lactobacillus or Bifidobacterium. These can be obtained by taking supplements or foods that have naturally live cultures in them such as sauerkraut, yogurt, kimchi and pickels. But it does not necessarily mean these foods or the supplements have the adequate amount of the key probiotics you might need that are unique to you. Symptoms may arise such as experiencing loose stool, but this should not be of major concern and should disappear in short order.