I don't have Crohn's but I do have what my GI Dr. calls a very nervous stomach. Suffered for almost 2 years with constant Diarrhea and went through every test known to man. Luckily everything was fine so both he and my PCP told me to take a Probiotic that also said Acidophilus on it.
I buy the Schiff brand as it is one of the less expensive and it doesn't need to be put in the fridge. Mine says you can take one or two per day. I only take one about 4-5 times a week as they have really helped me.
Hope this helps...JJ...