It's not that I 'trust' big pharma - it's that I look at all the sources giving me information, and pick the one that has the least chance (with my estimates of reliability of information) of my children getting seriously injured.
Everyone has to make money - big pharma to alternative therapist. Big pharma is held to standards, and when they are discovered to have done something dodgy, they are taken to court and this is publicised.
This is the same for everyone - although unlike big pharma, alternative therapists aren't actually held to a provable standard so can't be taken to court (unless they actually manage to kill someone).
As a noticeable example, take the new european directives on supplements actually having to be able to prove that they have the effects they claim, and the horrified yells coming from 'big herbal' over it.