This is the 4758th most frequent Chinese word.
管用
Effective; useful.
管用 is used to imply effectiveness or utility of the medicine in curing the cold.
这药很管用，感冒立刻好了。
This medicine is very effective; the cold was cured immediately.
管用 expresses the possibility of being effective here, presenting uncertainty.
我的建议可能不管用，但你可以试试。
My suggestion might not work, but you can give it a try.
管用 is utilized to display the utility of a method for problem-solving.