to prescribe the right medicine for an illness

Literally "to prescribe the right medicine for an illness", meaning to study a problem to find the right way to solve it or to take appropriate steps; appropriate steps.

(variant form) to prescribe the right medicine for a specific illness; to take the appropriate steps to solve a problem

a system of medical treatment that treats disease by producing effects different from or incompatible with those of the disease being treated; symptomatic treatment