I am a patient of Dr. Dahlman. He is not a quack. He does not know everything there is to know about ibs, but he knows alot. He knows more than alot of medical doctors out there. I have been to quit a few. I even went to a gi specialist. What a joke! I have been a patient for about 2 months now. I am not cured yet but have had improvement. No one is perfect and everybody has thier own ways to fight a disorder that has no obvious causes. Of course there will be dissagreements when no one knows the cause of ibs. If they knew then we all woudn't be here trying to figure this hellish disorder out!