The danger of diarrhea and watery diarrhea for more than three days is determined by the frequency of diarrhea and the amount of diarrhea each time. If the diarrhea is more than three days old and the frequency of diarrhea is high and the amount of diarrhea is mostly yellow and watery, and if it is accompanied by nausea and vomiting, then it is necessary to rule out the possibility of electrolyte imbalance or dehydration. If a patient has electrolyte dehydration, there are usually dehydration symptoms such as dry mouth, thirst, loss of skin elasticity, and sunken eyes. This is especially dangerous for elderly patients with other cardiovascular diseases, because it may trigger some attacks of heart or liver and kidney diseases. Therefore, it is dangerous for patients with more frequent cases of dehydration and who are older.