The only thing I could think of is Epic II CL to help with colic. I haven't used it but actually do have a gallon of it. I heard good things about this.
Equine Colic Relief.... I used it once, did nothing. If the company ads are to be believed it's nothing short of a miracle but I have never heard a first hand endorsement from someone who has used it successfully. Would be nice if it were a fix-all.
Makes me wonder... is simethicone used in horses for gas colic? It seems like it would help. I've heard of whiskey as a colic remedy, and I've personally used Valerian capsules for pain relief and sedation.