Final answer:
The effective dose-50% (ED-50) is the dose of anesthetic that causes 50% of patients to become unresponsive to painful stimuli.
Step-by-step explanation:
The dose of anesthetic that causes 50% of patients to become unresponsive to painful stimuli is known as the effective dose-50% or ED-50. This is the dose that results in a significant response in 50% of subjects. It is important to note that the ED-50 is different from the lethal dose-50% (LD-50), which is the dose that is lethal to 50% of a population of test animals.