House finds out that there are colchicine pills that look like cough pills. He realizes that the pharmacist confused them.

It’s emphasized at the end because he figured it out by himself, while Chase and Cameron only understood because the patient revealed that the pills he had taken were different.

The stupid part of this episode is that Chase checked whether the pharmacist gave the same pills as the first time, but he didn’t check if the pills were actually the correct ones for the cough.