I have had this in the past. Now your going to have to go the thing where they make you wait and pick you. You may not even end up having to go. WHen they call you they will ask you questions. I got out of mine by a few ways I have gotten out of Jury duty 3 times. I tell them I have family in Law force that will greatly sway my opion I also tell them I will be disruptive to the ct because I can not sit still for longer then 15 min due to my health conditions I have a bladder condition that can not be controlled with meds. Now be kinda rude or obtnoxios. If you know a little what the case is on that can have upper hand. My friend whent for pot trial. SHe got oh america she did a lot of drugs.They dismissed her after 5 min. Another trial I was on was against a black man I did pretend to be rasist even though I am not I was also let go with in 10 min. When i told them about my health conditoons they didnt ask for proof i just put a fuss up and they let me go. Ya got to poor it on thick and act like a pain in there but they will not want you in there ct.

My husband went to jury duty once and saw a potential juror try to "lay it on thick"... The judge or whoever, caught on and they were held in contempt of court and fined.  Lots of people do not want to do jury duty for whatever reason and lawyers and judges are saavy to this.  I do not have to do jury duty because I am a caregiver to two small children (I stay at home with my kids)  Perhaps you can go to a doctor and get diagnosed with IBS (which we all probably have anyhow)... There is no official test for this... You just mention symptoms and then get the diagnosis? 

Hi Mary,
I was a law clerk for a judge here in Philadelphia, so while I can't speak to the courtroom procedures for the court you will be going to, I can tell you what I have seen in our courts here. I don't know if you have only received the card in the mail saying "It's your turn" or if you have actually been called in. If you only got the card in the mail, it is possible you will not even be needed -- make sure to call the number on the car the day before to see. If you do already know you need to go down to the courthouse, you have several opportunities during voir dire (jury selection) to get dismissed.
During voir dire, each side's attorney gets to ask the jury pool questions. This helps them determine who they want on the jury. (sorry if this is all information you already know. I find it makes things less stressful when l to know exactly what I am getting into, so I wanted to give you too much information more than not enough). Usually there is a question regarding health issues, such as does anyone have a health issue that would prevent them from serving on the jury. At this point, you should say you do, and then you can request a side bar. Side bar means you go up to the judge, and the two side's attorneys join you, and you can then tell them about what IC means, in privacy. Be specific, and don't be shy so they really get the picture. There may be other questions where this information is important, and you can always request side bar when answering a question.
In the event that you are selected for jury duty, we allowed jurors to have their own water during the trial. I also would imagine if you need to bring your own food for health reasons, the judge will most likely allow you to keep it in the jury room, where there is frequently a small fridge. You can also always request to go to the bathroom. All that said though, each judge gets to make the rules for his or her courtroom, so it helps when you have a kind judge. There is always the possibility that you will get a meanie, but let's hope that doesn't happen. Usually though, if the attorneys think you might cause a disruption, or truly be uncomfortable, they won't choose you.  
I hope some of that was helpful. Good luck!

Or you can try as I did to get out of it altogether on the form they sent you - the section for excusal for medical reasons - if approved you can't be called for a year.   I went into my prior urologist's office, holding my stomach, looking like crap, telling the office people I'm still suffering w/ IC and I just got summoned for jury duty and there's no way I can serve, can the doc please take 2 min and fill this out for me?  (It's only a few lines plus his license # & signature.)  I said I would come back later that day to pick it up personally to minimze their efforts & ensure I got the papers. 
This was towards the beginning so I had seen him recently so that might've helped, but I would try it now too if I had to.

I got out of jury duty altogether when I was called for it several years ago.  I called my doctor, who wrote an excuse for me that I needed to be in the bathroom really often.  I can't remember where I submitted it, but I think I remember taking it in to the justice's office or something.  There was absolutely no problem getting excused from the jury duty.  They didn't want me once they found out I couldn't sit there for long.  I think you can get out of it pretty easiily.

finally, a benefit to ic!  i just went to the clerk's office, cried about having ic, and they told me i just had to wait until noon and let me go home!  this was in brooklyn--and they didnt even make me mail in a doctors note.  fyi.