For those who think it may be due to something in your dog's past, my little dog had no problems with thunder until just the last 2 years (he's 8). I've use Bach Rescue Remedy and Storm Stress (vet recommended). I think those who've advised that the owner stay calm and project that are right. Our dog seems to respond best to being put in his crate. (Holding him doesn't help at all.) When I see/hear a storm coming, I give him the homeopathic remedy, sit near him (my foot pushing against his butt seems to help), and speak calmly to him. If he gets too agitated, or if he wakes us up in the middle of the night when a storm comes before we're aware of it, he goes to his crate. I think you have to try all these suggestions and see what works for your dog. (We're thinking about trying the thundershirt, too).