I have been constipated the past 4 days and until today i went but i saw red bright blood , should i be worried about colon cancer?

Not really: While anytime we doctors hear bleeding from the colon, we of course "worry" about cancer, but a little bright red blood especially in the setting of constipation is overwhelmingly likely due to a little hemorrhoid or mucosal tear (ie a small cut). If it keeps up, get checked out, but if it's a one time thing, i wouldn't worry.

Get evaluated: Anytime you see blood in your stools it should be evaluated since this is a possible sign of colon malignancy. Most of the time bleeding the result of other causes and colon cancer would be unusual for someone of your age. It is likely that when you passed hard stools after 4 days of constipation that you open up a small fissure. Get checked out anyway.

See an MD: Your doctor will examine you first. Hemorrhoids are a more common cause of bleeding from the rectum than colon cancer. Furthermore, you are only 24 which is a young age to get colon cancer. See your doctor.