Nervous puppy?

Question
Hello Jana, I adopted a 6 month old, male, neutered, terrier mixed breed, 30 lb puppy from a local shelter. He seems to be doing fantastic and has received all his vet treatment since I got him at 8 weeks. He has received all his shots (4 sets of DHLPP, Rabies, and bordatella) and is current on worming, flea and tick treatment, and heartworm prevention. I have been taking him for walks around my apartment for a while now, since he finished his shots, and he has seemed to be ok. Over the past day or so I was taking him to a local public park to walk on a trail. In order to get to the park he has to take a car ride, which I have done since he was young for the vet, and has always and still does get car sick. Often his reactions to the car are just wining and pouting; however, it has happened that after a car ride he will vomit once but it does not happen every time. I noticed that he seems to get diarrhea when I go to the park and after the car ride, is this normal? In the morning and if we dont go out his bowl movements are normal, is it ok for him to have diarrhea in response to walking in new areas and car rides? He is wormed and current on vet care but is there something he could have in terms of health where he can have a very normal bowel movement the first time he goes and then it turns to mild diarrhea or is it likely from stress? I am going to take him back into the vet for a check up this week but I wanted to research alittle so I could explain how the events occured and I also like to educate myself about what could be going on. I think the diarrhea has only been after walks in new places and car rides but it really seems whenever he goes outside for any walks. He will have one normal bowl movement and then the rest after this will be mild diarrhea and the next day the cycle starts over, is this a medical concern or anxiety? He is acting very normal otherwise, very active, eating, playing, drinking, and typical happy puppy. Any ideas about what might be going on will be great, I want to make sure he is happy and I enjoy my walks with him and hope if it is from anxiety it will go away or I can figure out how to deal with it.

Answer
Rachel,
you have asked a question that veterinarians have asked for generations. How is it that a perfectly healthy dog that has a bowel movement in the waiting room as it is walking into the exam room have it change from a solid stool to pudding-like diarrhea in about 15 steps?

There is no answer because the only conclusion most of us can come up with is nerves. Why and how a nervous dog creates instant diarrhea is a mystery but considering the fact that when we have butterflies in our own stomachs, or a nervous stomach, some of us vomit or have diarrhea ourselves.

Churning up all that stomach acid could be a part of that but how it happens right in the intestines is the mystery.

Car-sickness may be outgrown but some dogs are car sick for life. Ginger helps with car-sickness in people but I am not sure it is safe for dogs.

But you have a healthy dog Rachel and what he is experiencing is totally normal. The park makes him nervous (he smells all those dogs) so that is why he gets the diarrhea there. The car ride he associates with feeling sick so he whines when he gets in the car and then vomits anyway- so that is a cycle. When it doesn't make him sick anymore he will stop associating the car with the being sick.

He sounds like he is doing great. Be careful of dog parks as they are hotbeds of parasites (hookworms, whipworms,etc) and viruses such as parvo.