The document discusses two common health issues related to the digestive system: cavities and digestive troubles. Cavities are caused by plaque that forms on teeth from food remains and produces acids, so the document recommends brushing teeth, minimizing sweets consumption, and visiting the dentist. Digestive troubles like constipation and diarrhea can be caused by diet, lifestyle factors, or having too much or too little water in feces. To avoid these issues, the document recommends eating a balanced diet, foods rich in fiber, and exercising regularly.