Where for example the basic diet advice has already been followed and where the dog is found to be generally OK and without blood in the faeces. 
Remember that diarrhoea is a common side effect to medications

As we discussed, I suspect that your dog has developed diarrhoea due to a dietary change or indiscretion which is likely to have changed the bacterial flora in the intestine. Such a change of the bacterial flora is a very common cause of diarrhoea in dogs. This is because such a change causes the intestine to become irritated and unable to absorb certain nutrients from the gut contents. The result is diarrhoea. The most common cause of this is a sudden change of diet or eating something the dog has found that its digestive system is not accustomed to.

As there is no blood in the diarrhea, and because your dog is behaving normally and showing no other signs of illness, I recommend that you start by adjusting your dogs diet as this is often all that is needed to get the intestinal function back on track.

It is important that your dog has access to plenty of fresh clean water.

Most cases will improve within 24-48 hours and completely resolve within less than a week following this dietary change.

- Start by feeding a low-fat diet consisting of cooked rice and a low fat protein source of boiled chicken or lean white fish. Mix about half boiled rice and half boiled chicken or white fish into the serving. Offer this diet to your dog in small portions 6 times a day the first day (about every 3 hours).

- If this goes well, you can gradually increase the amount of food offered per meal and reduce the frequency of meals to 3-4 times a day.

- Continue to give the until the dog's gastrointestinal function has returned to normal. When the stools have been normal for about a week, you can start to gradually mix the original food source into each meal. Make this transition back to the normal food over 5 days.

-In addition to a bland diet, you can supplement with veterinary probiotic. Probiotics can sometimes help establishing a healthy gut flora more quickly as they contain healthy bacteria. An example is Pro-Kolin from Protexin can be bought in pet stores such as Pets at Home. Give these supplements as directed on the packaging.

Monitor you dog closely and take the temperature twice daily if possible. The normal temperature in dogs is 37.5-39.0 degrees Celsius.

Contact your veterinary surgeon if you see any other signs of your dog being unwell such as:

-          Blood in the faeces.

-          Dark faeces (melena).

-          Straining without producing faeces.

-          Reduced appetite.

-          Elevated temperature.

-          Vomiting

-          Lethargy or dullness

If the diarrhoea persists without signs of improvement for more than 48 hours after keeping on the bland diet and probiotics, then you should contact your usual veterinary surgeon for further advice.

If you have changed the dog’s diet on purpose you may expect loose stools for a couple of weeks, a gradual changeover where the new food is introduced slowly as part of the ration may make this problem less likely.