Placebo: Once a dirty word, it might be your new best friend!

The placebo effect is one in which a patient’s symptoms are alleviated by an otherwise ineffective treatment because of his or her mere expectation that the treatment will help fight the disease.

But.. the key question here is: if the placebo effect can alleviate symptoms, how can the treatment be labelled 'ineffective'? It is, by definition, surely highly effective if it alleviates symptoms.