Healthy digestion is so important, yet often taken for granted—until something goes wrong. Whether it’s killer heartburn, stomachaches, diarrhea, gas, bloating, constipation, nausea or vomiting, gastrointestinal woes can wreak havoc on your life. Find out how certain ailments—including heartburn, GERD, Crohn’s disease, and ulcerative colitis—can affect digestion, what to do about them, and the best ways to keep your gastrointestinal system in tip-top shape.