Some frauds and falsification happen but as with any scientific study they have to be later repeated and peer reviewed by independent group of scientists. Sooner or later any fraudulent scientific study is going to be exposed.
Some examples of such studies:
http://healthland.time.com/2012/01/13/great-science-frauds/ (includes Dr. Andrew Wakefield)

Anti-vaxxer "hero" fraud
http://www.bmj.com/content/342/bmj.c7452.full
http://edition.cnn.com/2011/HEALTH/01/05/autism.vaccines/

Scientific method and evidence do not care about someone's bias and belief. The truth will come out anyway. Someone may believe that the Earth is flat disc but it won't make it so.

That's what happened with bad science and pseudoscience such as colloidal gold or anti-vaxxer claims. They just within time couldn't cope with the burden of proof provided by extensive international scrutiny. There were statistical reviews and meta-analysis which were performed by independent researches from all over the world, which ultimately exposed these studies/claims to be false.

That anti-vaxxer conspiracy is a great example of the Dunning–Kruger effect‎. It is cognitive bias in which unskilled, uneducated, individuals suffer from an illusory superiority of their knowledge and skills, that makes them to overestimate their abilities in critical thinking and knowledge of a field, as much higher than they actually are.