Many medicines taken by mouth may affect the digestive system. These medicines include prescription ( 处方 ) and non-prescription ( 非处方 ) or over-the-counter (OTC) products. Although these medicines are usually safe and effective, harmful effects may occur in some people. OTC’s do not often cause serious side effects. It is important to read the label to find out the side effects, warnings, and when to consult a doctor. Always talk with your doctor before taking a medicine for the first time and before adding any new medicines to those you are already taking. Tell the doctor about all other medicines you are taking. Certain medicines taken together may cause harmful side effects. In addition, tell the doctor about any allergies to foods and medicines and about any medical conditions you may have such as diabetes, kidney disease, or liver disease. Be sure that you understand all directions for taking the medicine. If you are an older adult , read all directions carefully and ask your doctor questions about the medicine. (178 words)