There once was a member of the gentry named Hu who had a servant named Erh-man. One autumn, Erh-man came down with a severe case of the chills and fever. He couldn't do any work, and his master didn't like the idea of having a sick person around the house.
"Erh-man, we can't use you any more," he said. "You'll have to go!"
"But Master, you know I don't have any family or relatives. Where do you expect me to go?"
"That's not my problem. If you can't work, you can't eat. How can I keep feeding you for nothing?"
"I've worked like a horse all these years," Erh-man pleaded, "and I never expected I'd wind up like this. All right, I'll go tell everyone what's happened and see what they say."
"Uh-oh," his master thought. "If the other servants find out about this, who knows, maybe they'll refuse to work anymore."
"Erh-man," he said. "Since you're so sick, you ought to find a place to rest and recuperate and come back when you're feeling better. How's that sound? Now here, take your wages and be off!"
There was nothing he could do but leave.
Erh-man walked and walked until he sank to the ground and could go no farther. He was hungry and dug up some grass with his bare hands to fill his belly. He lay like this for seven days and had eaten all the grass within reach, when suddenly he recovered. Then he returned to his master to work.
Not long afterwards, Hu's only son came down with the chills and fever just as Erh-man had.
"None of the doctors can cure him," Hu thought. "I've got it! I wonder how Erh-man got better? I'll go ask him."
"What kind of medicine did you take to get over your disease?" Hu asked.
"After I left you, I walked next to a pond outside the village and dropped to the ground. I was hungry and thirsty, and I lived on the grass there to get by."
That type of grass was often used by Erh-man as brush for kindling. When Hu's son ate some of it, he was cured.
And that's how the plant got its name, ch'ai-hu. Ch'ai means firewood or kindling, and hu is the name of Erh-man's master. Its English name is Chinese thoroughwax, or Bupleurum Chinese.