Hi, I had gone through your question I can understand your concern about your friend. As harpic is very much acidic it s pH value is between 3-4 which is two much acidic and can cause stomach injury and even lead to gastric ulcer, so it may bleed but it is neutralized during further passage. If your friend has Terry black stools that means the bleeding from stomach and is because of Harpic. If the blood is red it is from lower intestinal hemorrhage which may or may not be related to Harpic. In any case if bleeding is continuous and he feels dizzy and fatigue he must consult the general surgery department. During mean time avoid oily, spicy, pickle, junk foods and take pantoprazole in morning empty stomach. Hope you will find my answer helpful. Regards Dr Muzaffar.