In the Spring and Autumn Period, King Jing of the State of Jin fell ill. One night he dreamed that the disease turned into two small figures talking beside him. One said, "I'm afraid the doctor will hurt us." The other said, "Don't worry. We can hide above huang and below gao. Then the doctor will be able to do nothing to us." The next day, having examined the king, the doctor said, "Your disease is incurable, I am afraid, Your Majesty. It's above huang and below gao, where no medicine can reach."
This idiom indicates a hopeless condition.