If you accidentally eat moldy bread, you risk experiencing unpleasant symptoms such as nausea, vomiting, and diarrhea. While most cases of ingested moldy bread won’t lead to anything serious, it is important to note that getting sick from moldy bread is possible, though rare. Some molds can produce harmful and invisible poisons called mycotoxins, which may spread through bread, particularly when mold growth is heavy. Eating moldy bread could make you sick, and inhaling mold spores could lead to breathing problems, including asthma. If you suddenly develop symptoms such as shortness of breath, nausea, an elevated temperature, or diarrhea, you should immediately seek medical help. It is best to throw away bread that has visible mold on it, as the microscopic roots of the mold can spread quickly through porous bread, and there is no way of knowing by sight whether a mold is safe or harmful.