If you have had diarrhea for 2-3 days and it is not improving, it could be caused by food poisoning, gastroenteritis, or other factors. It is recommended to have light foods like soups, broths, toast with butter, eggs, and crackers, and avoid heavy or sweet foods like red meat and undiluted fruit juices. Make sure to drink plenty of liquids, either cold or hot according to your preference. If the diarrhea persists for more than 7 days without improvement, it is advisable to consult a doctor for further evaluation.