I occasionally take laxatives and have been taking Ducolax Sensitive for the past 2 days, but my stool just had pretty bright red blood appear?

HemorrhoidalBleeding. Generally, small amounts of blood with stool occurring with constipation in an 18 year old person is likely from internal hemorrhoids that are bleeding, more so if he blood appears mainly in the water or on the toilet paper and not covering the stool. If the bleeding is persistent, recurrent or of large amount consult your physician. For information on constipation: http://bit.ly/1uzOegm.