[header] How to handle know it all friends giving medical advice [title] Accept that people may not behave as you'd like. [step] Know-it-all friends may give advice thinking that they're being helpful. Unfortunately, they might not realize that they're doing more harm than good. 
Rather than getting upset or frustrated, learn to accept that some people just don't behave as you'd like. [substeps] While you can't control what other people say and do, it's important to feel in control of your own behaviors.