Got The Answer But Can't Parse It

[belido]

24a) This dose is sure, when mixed, to produce a possible cure (7)

The answer is "placebo" (it has been accepted on-line) but I can't parse it!

[dannyk13]

anagram of a possible cure minus is sure

[Toorak]

Anagram of a possible cure minus is sure

[mac44]

a possible cure minus is sure.

[belido]

Ah! A subtractive anagram missed that thank you both very much.

[belido]

And thank you Mac44 as well.

[qadzbork]

Take “is sure” out of “a possible cure” and you’re left with an anagram of”placebo”