Is it dangerous to be constipated for 3 days?

Bowel habit: This depends on your usual bowel habit. I suggest bran, fiber, oatmeal, grain and 8-10 glasses of water /day.

No: No, this isn't dangerous, but it can be quite uncomfortable. Increase the fiber in your diet, e.g. psyllium, bran cereal, or, if you become uncomfortable, an over the counter stool softener would be a safe treatment.

Depends: If you are having severe nausea and vomiting with inability to pass gas, then it can be a problem. Otherwise, the stool would just get very hard and can be painful to pass. To keep bowel regular, make sure you drink at least 6 glasses of water a day, eat plenty of vegetables/fruits, and stay active.