Answer:
Eukaryotic pathogens (parasites, fungi) infections are harder to treat because these pathogens have cells very similar to the human cells. Therefore, it is hard to find a drug that targets only pathogen and not normal cells. This is the reason why many drugs used to treat these infections have severe side effects and must be administered carefully.
On the other hand, antibiotics, used to treat bacterial infections, target prokaryotic cells, so human cells won’t be targeted.