Alternative medicine is big business. With a cost of more than $2 billion annually in Australia, you might think practices like vitamin and mineral supplementation, acupuncture, naturopathy, homeopathy or even chiropractic care were conventional. Yet the majority of these have little foundation in evidence. So why are so many of us signing up for treatments with no guarantee of success? At least some of the fault lies with doctors like me.

Effective communication has long been considered a key component of medical care. Patients want to know how likely a treatment is to work and doctors should be able to tell them. This is the promise of evidenced-based care, yet in some regard doctors are failing to promote it.

Patients want to know how likely a treatment is to work and doctors should be able to tell them.

Generally, evidence-based practice has helped to increase both the safety and utility of many medicines. This comes at the cost of losing the "power of suggestion" that occurs when proof is absent. Alternative medicine does not suffer this dilemma. When a substance has not been tested in a well-designed trial it is impossible to say it doesn't have a benefit. When the purported effect is vague, such as wellness or immune defence, it is easy to convince yourself it is working. The mystery is maintained.

But explanations from doctors about why evidenced-based medicines are more effective than alternative medicine are not just poor at the patient level. Broader communication, which has a better chance to affect opinion and understanding, is frequently squandered by those on the soapbox.