Answer:= Amensalism, association between organisms of two different species in which one is inhibited or destroyed and the other is unaffected. There are two basic modes: competition, in which a larger or stronger organism excludes a smaller or weaker one from living space or deprives it of food, and antibiosis in which one organism is unaffected but the other is damaged or killed by a chemical secretion.
Here human beings are unaffected and medicine destroyed(so second mode of amensalism here)