After coming back from our camping trip at Tahoe, I had a stomach ache which got worse over time. My hands and feet got colder and my face was turning white (whiter that is), bad signs. When all the usual over-the-counter medicine didn't work, I asked my wife to bleed my thumbs.
Bleeding the thumb is a traditional korean home remedy for upset stomach with symtoms I described above. The practice is common enough in Korea that you can buy a specially designed needle at korean drug stores. Outwardly, it looks like a pen but when you press the button at the back, a needle darts out quickly to punch a tiny hole. In absense of such a device, you can just use a needle or anything sharp and pointy.
Before bleeding the thumb, you have to push bad blood toward the thumb you are tapping. This is difficult to explain but it is done by sweeping one's hand across the body toward the thumb. While one hand is doing that, the other hand holds the thumb at the bottom to keep the bad blood from flow away. A few sweep is enough. Once this is done, the thumb should look really red. Now bend the thumb toward the palm and punch a hole just above the thumbnail. If it was effective, you should see really dark blood coming out. If it is done well, your stomatch should feel as if someone pushed the flush button.
I ended up bleeding both of my thumbs. My wife is not that good at it so there was no flushing. Still, my hands and feet got warmer and my face returned to normal color. Pain subsided as well so I was able to watch Kung Fu Hustle with my wife.
Anyhow, I don't know how it works but I do know that it does help if it is not abused. You should not be bleeding your thumbs repeatedly. If it didn't work the first time, it won't work the second time.
Another effective yet less bloody korean home remedy is putting a grain of rice or a small piece of rock under a bandaid to ease throbbing pain. My guess is that it creates noise in the nerve system that interferes with the throbbing pain.