Your friend is absolutely right. Pain killers like aspirin can cause stomach bleeding.In fact people shoould not take aspirin if they have liver disease , kidney disease or peptic ulcer. If you are a regular drinker and consume 2 to 3 pegs of alcohol daily you should consult the doctor before going for aspirin becoz for chronic alcohol drinkers aspirin increases the risk of stomach bleeding.

Can conditions such as stomach acids formation also lead to the said bleeding problems, this is something which I overheard from one of neighbors regarding her wife.

Yes there have been several such cases of the stomach acids being responsible for causing inflammation which in turn may consequent to the said bleeding of the stomach. The formation of such stomach acids is usually attributed to the conditions of heartburn and this situation is also referred to as esophagitis or inflammation of the esophagus. In such conditions there is necessarily a lack of coordination between the esophagus and the stomach which causes the muscles in between them to malfunction and as a result they do not close properly which again reverts the consumed foods toward the esophagus. Again apart from this another condition is also known to inflict such bleeding problems. In such cases the veins which are present at the lower end of the esophagus bursts and in turn cause significant bleeding to occur. In addition presence of secondary diseases can also lead to such bleeding like that of coughing problems leading to excessive pressure in the abdomens, hiatal hernia or even the esophageal cancer can all sum up to this cause.