If the social atmosphere almost entirely revolves around Greek Life than go for it... Otherwise you'll be miserable and constantly ask yourself and regret not joining one. Not worth it if it's not predominant. Yes, pledging and premed are like mixing oil and water. Try to get a feel for which fraternity you want to pledge and ask around (not to the brothers of course) what the deal is: do you get sleep deprived? Physical? Gross? Cleaning? Then it ultimately becomes a personal decision where you have to be 100% honest with yourself: are you capable of ONLYpledging and studying (possibly some sleeping) for an entire semester? I did it and was miserable for the entire thing. But when it is over, you feel accomplished that you maintained a good GPA and are now a brother. No semester since then has been harder since then; everything else seems easier now. But be warned it is extraordinarily difficult and will test you to the limits...