If your 4-year-old daughter is experiencing diarrhea and is unable to leave the toilet, it is important to make sure she stays hydrated. You can give her oral rehydration solutions that contain sugar, salt, and electrolytes to replace what is lost during diarrhea. It's important to watch for signs of dehydration such as thirst, decreased urination, dark urine, sunken eyes, fatigue, or confusion. If her symptoms worsen or if she shows signs of significant dehydration, it's recommended to seek advice from a healthcare professional. If you notice blood in her stool or if the symptoms persist for more than 48 hours, it would be best to consult a doctor. Additionally, if other symptoms like fever, abdominal pain, or a general decline in health appear, it's advisable to seek medical attention for a new evaluation.