How can one deal with know it all's

[Shadowstalker]

I live with two folks that are know it all's my husband and a gal pal of mine, my gal pal is worse, she thinks that everything she has read, without real research, is the beans, the A.M.A. books are not lying to her (according to her) and so on, she also doesn't want to be told she is wrong, she has stated that to me face a number of times. she is on webmd as i type, spouting out redderick, but what she doesn't get is that any meds (prescribed)have been and has been used for more the one disorder, she doesn't get it.

Basically how do you deal with a person that doesn't want to hear that they are wrong no matter how polite you are them.. If i wasn't living with them it would not be a problem for me i would just say "whatever ok whatever" and then walk away. but living with it and no place to go, presents a problem for me. I am a listener first, and then if i feel they need advise i will give it..

I am not above lightening to the advise of others, so that's why I am asking.

If this is in the wrong section plz put in right place and let me know where it is..

thank you