During the acute phase, it is usually not possible to eat or drink any food or water, so that the intestines are fully rested and, if necessary, nutrients are infused intravenously. It is recommended to start with easily digestible liquid food such as gruel and soup, followed by semi-liquid food such as rice. Finally, a normal diet should be resumed, but care should be taken not to eat cold, raw and irritating foods to avoid burdening the gastrointestinal tract.