Despite all the evidence from properly conducted experiments and trials which show that homeopathy is a lie, a large numbers of people still think that homeopathy is real and not a placebo effect. Their delusional mindset is something that will be hard to rectify; witness the still quite large numbers who believe in astrology and other woo-woo phenomenon.
What we can do, is continually point these people to the evidence and explain the processes that underlie the scientific process in the hopes that they can use critical thinking techniques to cut-out all the chaff that exists out there and concentrate on the pertinent details and reach their own conclusions. It will be slow and hard process. A good place to start is reading Ben Goldacre’s http://www.badscience.net/ site, and in particular, his latest article The end of homeopathy?