Most people can enjoy fermented foods, but some should be cautious. Those with weakened immune systems, severe medical conditions, or gut disorders like IBS or IBD should consult a doctor before consuming them. Pregnant individuals may benefit from fermented foods, but should follow medical advice. Some fermented foods contain histamine, which can worsen inflammation in people with Crohn’s disease, or tyramine, which may affect blood pressure.

Some people may experience mild bloating or loose stools when first adding fermented foods to their diet—this usually improves as the gut adjusts. Safety depends on how the food is made and handled, whether it contains live microbes, and if it's raw or pasteurized.