prescription vs recipe

[Themak]

English Language Tests, Intermediate level

ESL/EFL Test #149 "Financial and bank expressions", question 7

The psychiatrist gave his patient a ......... for some medicine.

(a) recipe
(b) statement
(c) prescription
(d) receipt

English Language Tests, Intermediate level

ESL/EFL Test #149 "Financial and bank expressions", answer 7

The psychiatrist gave his patient a prescription for some medicine.

Correct answer: (c) prescription

Your answer was: incorrect
The psychiatrist gave his patient a recipe for some medicine.
_________________________

Why not recipe?

Themak

[Conchita]

For the difference in meaning between 'prescription' and 'recipe', please have a look at these definitions:

recipe
prescription

[Ryho]

Hi,
but the
http://dictionary.reference.com/browse/recipe
says, that 'recipe' is 'a medical prescription', so why not?
ryho