pa stool exam mo and check for worms. pero while waiting for diagnosis, why dont you try giving probiotics? probiotics are good bacteria naturally found in the intestines, they aid in digestion and act as the body's natural defense against infection ( esp gastric type). these are depleted if dogs have been exposed to antibiotic treatment or eating processed food( cooking kills good bacteria found in food). na try ko to sa mga dogs namin before because they had similar symptoms but the vet could not figure out the cause. gumaling sila.  
 
good bacteria is found in yogurt or yakult but if your dogs cannot tolerate lactose, meron naman lactose free na probiotics found in health stores sa malls.

Quote from ethan on Jul 20^th, 2010, 8:38am:

 
I suspect protozoan iyan.  But best for the vet to confirm with the stool examination.  Good luck.

baka amoebiasis yan. usually transmitted through fecal-oral route.  metronidazole will do