Fermented foods are considered safe for most people. However, some individuals may experience side effects.Due to the high probiotic content of fermented foods, the most common side effect is an initial and temporary increase in gas and bloating. These symptoms may be worse after consuming fiber-rich fermented foods, such as kimchi and sauerkraut. It’s also important to note that not all fermented foods are created equal. Some products may contain high levels of added sugar, salt, and fat — so it’s important to read nutrition labels to make sure you’re making a healthy choice. If fermenting at home, make sure you follow recipes closely for safety purposes. Incorrect temperatures, fermentation times, or unsterile equipment can cause the food to spoil, making it unsafe to eat.