Many people enjoy salads and eat them regularly. Salads can be an excellent choice for a healthy person, whether used as a side dish or eaten as the main entrée. It is not uncommon for someone to get diarrhea after eating a salad, especially if it is made from lettuce. Salads made from lettuce that have not been properly washed or fruits that have not been cleaned properly can cause diarrhea when consumed by the person eating the salad.