I mixed aspirin powder with orange juice, and my stomach only hurt until many days later. I didn't know this was due to the aspirin, and I did this for a month or so with crippling stomach aches every single day until I stopped putting it in. When I stopped taking it, my stomach didn't stop hurting immediately, but it took a few days. Likewise, I also put aspirin powder in my coffee, and the same thing occurred. RP recommended dissolving it in warm water, but the powder does not dissolve completely even in plain warm water, but there is flakes of aspirin floating in it. Does it take time for it to dissolve? Do I need to filter out the undissolved flakes? I have no idea what I'm doing wrong, and nobody on this forum has ever had such a complaint. There was no bleeding, and my stomach rarely hurt in the past. The reason why it could take many days for the stomach to start and stop hurting could be explained by undigested flakes of aspirin building up slowly, and slowly leaving. Some member on this forum recommended adding aspirin to orange juice, but I have no idea how the smallest amount of aspirin could dissolve in cold orange juice.