The eldest son of Mr. Li, aged 19. In April, he suffered from cold-damage disease for nine days. The doctor treated it as a yin pattern and administered several doses of Aconite Middle-Regulating Pill, but the symptoms worsened. Another doctor considered it a yang pattern, but their opinions conflicted. Afraid to take any more medicine, he sought Luo's advice to resolve his doubts.

Luo did not want to directly state the diagnosis but carefully explained the differences, allowing the patient to judge for himself: In general, a yang pattern is characterized by high body heat, warm hands and feet without coldness, comfortable lying down, strength when rising, no aversion to cold but rather aversion to heat, no vomiting or diarrhea, thirst with a desire to drink water, dysphoria preventing sleep, good appetite with excessive talking, and a floating, large, and rapid pulse—these are signs of a yang pattern. A yin pattern, on the other hand, is marked by no body heat, cold reversal in the hands and feet, aversion to cold with a tendency to curl up while lying down, facing the wall when lying, disliking human voices, or covering oneself with clothes, no thirst or irritability, anorexia, normal urination, loose stools, and a deep, thin, and slightly slow pulse—these are signs of a yin pattern.

Upon examining his pulse, it was deep and rapid, six to seven beats per breath. He cried out incessantly at night, unable to sleep at all, and also enjoyed drinking ice water. All signs pointed to a yang pattern, and he had not passed stool for three days. Drastic purgation was deemed appropriate. Thus, six qian of wine-fried Rhubarb Rhizoma, two qian of Prepared Liquorice Root, and five qian of Mirabilite were prescribed and decocted for him to take. By evening, he passed stool several times, expelling over twenty dry, hard lumps. That night, he sweated profusely, and by the next day, his body was cool, and his pulse had calmed.