I would def. take him to the vet to make sure but it could be irritable bowel syndrome (IBS). This is what your vet will diagnose if there is no other serious problem because with IBS there are no apparent abnormalities. You still need to talk with your vet though because it is possible that your dog may have a more serious stomach problem.
Here's a link on canine IBS;
http://www.petplace.com/dogs/irritab...ibs/page1.aspx
Have you tried California Natural? This is a very healthy food and is specifically designed for dog's with either allergies or sensitive systems because of the concise list of ingredients.
You may also wish to try a home cooked or raw diet with your dog. This way you know exactly what is going into your dog's food and can eliminate ingredients one by one that may be causing stomach discomfort or loose stools. It's almost like an elimination diet. Keep a food journal if you wish recording what he eats and how he appears to be feeling.
Here are some natural remedies that may be helpful in the meantime but remember these may help with symptoms but do not solve the underlying problem unless this is in fact a disease such as IBS that has no cure but only treatment of symptoms;
First, here are some techniques to firm up a dog's stool;
Try giving your dog some canned pumpkin (not pie filler though!). This is a great source of fiber and will help firm the stool. It is great. It helps both constipation and diarrhea. Give the dog 1-3 tablespoons a day, depending on their size.
Here are some techniques for eliminating doggie gas;
Another approach you can use to minimize your dog's problem with gas is to add live yogurt cultures to your dog's food. Live yogurt cultures contain bacteria that will help to wipe out the nasty gas forming bacteria that are causing problems for your dog. (You can use straight yogurt from the store) Give 1-2 spoonfuls per day depending on size.
Try using Nux Vomica to reduce or eliminate the problem of flatulence. Nux Vomica (otherwise known as Poison Nut) is a homeopathic treatment that is very successful in the remedy of indigestion and flatulence in pets. You can purchase Nux Vomica through online sources or even at your local health or homeopathic stores.
Try activated charcoal – It’s messy, but it can absorb the smell pretty well. For small pets add 1/8 to 1/4 teaspoon to their food daily. For larger pets, 1/2 teaspoon is about right. Be aware activated charcoal can absorb nutrients as well as gas from the digestive tract. Don’t use it for more than a few days at a time.
Try a natural anti-gas product – PetAlive Flatulence Preventer combines selected natural herbal ingredients such as anise and fennel to effectively support efficient digestion and absorption of food which helps reduce gas production. I like Native Remedies Pet Alive products because they are all natural and are thoroughly tested.
Make your pet eat more slowly – I thought this was a really clever idea. You put a large object – like a ball- in your pet’s bowl. Your dog or cat has to nose around and work harder to get the food so they will forced to slow down.
Raise the food dish – If your dog does not have to bend their neck so far down they will swallow less air. You can place the food bowl securely on a box or you can buy a stand that holds food and water at mouth level. The stands are really nice. My mother-in-law’s Doberman used to have a stand that a neighbor made for him. The dog’s look so much more comfortable eating from a dish at their level.
Now, here's some info on general stomach soothing and comfort;
You may wish to try a probiotic supplement or a yogurt with live cultures. Here's a link to a natural probiotic supplement;
Soothe the Digestive System & Stomach Bloating in Dogs & Cats
MINT OR PEPPERMINT TEA
Now you might laugh at this one, but mint has long been known to have a calming influence on the gut. Simply make your mint tea as normal, and allow it to cool. Offer small dogs up to one mug per day. Large breeds can have up to three mugs a day.
There are many natural herbal and homeopathic remedies used to soothe the animal digestive system and help restore balance. Plantain is a well-known herbal remedy that uses mucilage to bulk up stools. Alchemilla vulgaris and Podophyllum are natural remedies, suited to animals that need digestive support in hot weather.
Arsen alb., a homeopathic remedy, helps to support both the digestive and the nervous system, making it an excellent choice for the ‘highly strung’ pet – that may have digestive problems related to stress and anxiety.
Put your dog on a ginger supplement or add some ginger root to his or her food. Also consider some nice ginger tea. Ginger will soothe the stomach.
Pepto Bismol comes in different strengths so it is important to choose the right one. Normally, regular strength Pepto Bismol is the safest type to use. The dosage of the medication will be determined by the size of your dog.
Generally, the advised dosage is 0.5-1ml of Pepto Bismol per pound of weight. It should be administered every 6-8 hours. If you're using the tablets, that is equal to ¼ tablet per 20 pounds of weight every 6-8 hours.
The medication will help relieve your dog's diarrhea but even if your pet seems to be fine it is a good idea to take him to see a vet as soon as possible. This is especially important if the symptoms persist or return when you stop giving your dog Pepto Bismol. In these instances, it could be that your dog's stomach upset is a sign of an underlying health problem.
*Point is, these are great remedies to try or use if your dog is disgnosed with IBS but tests must be done. Talk with your vet about this because there could very well be a much more serious stomach condition involved here.
Good luck and I hope your dog feels much better soon.