Probiotics

I travel with VSL #3 all the time. It's okay if it comes to room temperature for up to a week, but it's hard to know how carefully it was handled before you ever got it. Depending on the length of a trip (and my level of obsessiveness) I have used all of the following techniques at least once:
1) Carry it in doubled paper bags so it's less likely to warm up in transit.
2) Put it in Ziplock bags and pack those in a big, wide-mouth ice-filled thermos. Sometimes this method leaks, depending on the thermos.
3) Upon arrival at the hotel, put the VSL (in Ziplocks) in the ice bucket and cover with ice. Drain the water and replenish the ice about twice a day.
4) Choose a hotel with a refrigerator (e.g.Residence Inn)
5) Ask the hotel to providce a small refrigerator (these are sometimes noisy)
6) I haven't actually done this, but a diabetic friend suggested that the kitchen might hold it for me, if none of the above were practical.

Most baggage holds in the plan are not temperature controlled and thus very, very cold ( the contents of your luggage is usually freezing cold if you open it just after you take it off of the belt)...so I put any delicate foodstuff or meds in my suitcase..I used to bring cheese in from France in the good old days when it wasn't ilegal. It arrived nearly frozen...so if you need to, keep it cold, take it strait out of the fridge and put it strait into ziploc and then into a thermal bag (to carry frozen foods)...that should do it for the flight and then follow Scott's instructions for the hotel stays.
Sharon

Sharon's suggestion will often work, but if you're stuck on the tarmac in hot weather the baggage compartment can get quite warm. I take the opposite gamble and always carry it on.