context: When you have constipation that won't go away for 3 weeks or more, it's time to see a doctor for help. After your regular doctor checks for any problems, you may want to ask her to recommend a gastroenterologist -- a doctor who specializes in digestive system problems. When you call to schedule your visit, ask if there's anything you need to do (or not do) before you come in. For example, you may need to change how you eat in the days leading up to your visit. Be sure you have all the information that will help your doctor best treat you, like: A list of all the symptoms you've been having Your medical history, including any medications, vitamins, or supplements you're taking and any family history of digestive problems Personal information that could be affecting your health, like pregnancy, stress, or recent travel If you have questions you'd like to ask the doctor, make sure to write them down ahead of time and bring them with you. You may want to take a friend or family member with you to the appointment, especially if they know some of your medical or symptom history. They can be another set of ears to listen and remember information during your visit. Your doctor will want to know as much as she can about how your constipation is affecting you. In addition to getting your family and medical history, she may ask you: When your symptoms started and how long they've been going on Whether your symptoms stop and start or happen all the time If anything seems to make your symptoms better or worse Whether you're having pain in your stomach or vomiting How much you've been eating or drinking If you've recently gained or lost weight Whether you have blood in your stool or when you wipe If you have to strain to poop Basic tests help your doctor tell if you have chronic constipation and what may be causing it. They may include a rectal exam, blood tests, urine tests, and stool sample tests. They can be uncomfortable, but they give important information about what's going on. Your doctor will want to rule out any underlying health condition that may cause your problem. Tests that help your doctor see inside your intestines include: Flexible sigmoidoscopy. This test looks inside your lower intestine and rectum with a thin, flexible tube. The tube has a tiny camera in it. With the camera, your doctor can see what's going on in your intestines and check for a problem. Colonoscopy. This is very similar to flexible sigmoidoscopy, but it's a longer test because it looks at your entire large intestine. Your doctor may give you medication to help you relax while you have it. Barium enema X-ray. An enema is when a doctor injects liquid or gas -- in this case, a white liquid called barium -- into your rectum through a small tube. Barium helps problem areas or blockages in your colon show up on an X-ray. Tests that help the doctor figure out if you have a problem with your digestive system include: Anal manometry: This measures how well your anus works. It checks how tight the muscles around it are and how they respond to signals from your nerves. A technician puts a thin tube with pressure sensors and a balloon in your anus. Once the sensors are in the right place, she slowly pulls the tube out to gauge muscle tone and contractions. The test takes about a half hour. Balloon expulsion test. Your doctor will place a small balloon filled with water into your rectum and then ask you to push it out like you would stool. If it takes you longer than a minute to get it out, it tells your doctor that the muscles that help you pass a bowel movement may not be working the way they should. Defecography: This test helps your doctor gauge how well your pelvic floor muscles and rectum are working while you poop. A radiologist puts a barium paste in your rectum that mimics the feeling of stool. You sit on a toilet next to a video X-ray machine. First, you'll need to squeeze and hold in the paste. Then, you'll need to strain as if you're having a bowel movement. The radiologist looks for problems as you push it out. Colon transit time test. Your doctor will give you a small pill to swallow that has a radioactive marker. Then she will track how long it takes for the pill to pass out of your body. If it takes longer than 3 days, it means your digestive tract has a problem digesting food correctly. Once your doctor has the information she needs from the tests you have, she can recommend the best treatment for your constipation.