Hello Dear Black stool with orange bubbles is a matter of concern in any age. Black stool is due to blood in stool. This can be due to liver disorder or infection of lower GI track. Get your liver function test, stool for occult blood and Colonoscopy done. If you have no money than follow some instructions: Take higher fiber diet, avoid alcohol and smoking, chew your food properly, avoid fatty and oily food, plenty of water and can take laxative or stool softener. If this helps you than carry on with following the instruction otherwise you have go through the investigation and consult your doctor. Best Wishes and have a speedy recovery.