When you are deciding whether to use a treatment, you should think about whether it is more helpful than harmful, not just whether it is helpful. This depends on how big the good and bad effects are.
How big the effects are may depend on how sick you are or how likely you are to get sick. For example, medicine (an antibiotic) for a bad earache (pain in the ear) caused by an infection may be more helpful than for a not so bad earache.
It also depends on how important the outcomes are to you. For example, taking a medicine may reduce earache, a good effect, but also have bad effects, like diarrhoea. Some people may think that earache is a more important problem than diarrhoea, and they may be more likely to decide to use the medicine. Others may think that diarrhoea is more important, and they may be more likely to decide not to use the medicine.
REMEMBER: Ask yourself if the advantages are better for you than the disadvantages.