The key to understanding 服药 (fúyào) lies in contrasting it with its colloquial counterpart, 吃药 (chī yào), which literally means “to eat medicine.”
In Western culture, the difference might be similar to “take your medication” (more formal) versus “take your pills” (more casual), but the distinction in Chinese is sharper and more consistently applied. Using 服药 in a casual setting would sound overly formal and stiff, while using 吃药 on a professional medical document would seem unprofessional and simplistic.
The most common mistake for learners is not understanding the formality difference between 服药 (fúyào) and 吃药 (chī yào).
Think of it this way: 服药 is for the instructions on the bottle; 吃药 is for when you talk about the bottle.