Answer:
Drug synergy can be defined as the interaction between two drugs which enhances the effect of the drugs. The effect of the drugs in the body is enhanced and the effect inside the body of human beings can be unpredictable.
It can be either harmful or it can be beneficial as well. Sometimes when a single drug cannot work on the body then two drugs are taken together to enhance its effect.
It can be harmful in case of sedative drugs where the enhanced effect can be fatal for the person taking it.