How is “reduce to” used?

In The Favourite (2018), one line is: “It reduces swelling and inflammation”

Which movie is “reduce to” from?

The clip at the top of this page is from The Favourite (2018).

Phrasal verb

to force sb / sth into a particular state or condition, usually a worse one; to change sth to a more general or more simple form

Se oye en 77 películas

1
reduce sb / sth (from sth) to sth / to doing sth
to force sb / sth into a particular state or condition, usually a worse one
a beautiful building reduced to rubble
2
reduce sth to sth
to change sth to a more general or more simple form
We can reduce the problem to two main issues.

Definiciones del Oxford Advanced Learner's Dictionary, 9.ª edición

It reduces swelling and inflammation

En 8 películas · n.º 1