Hello, my name is***** and I have over 20 years of experience as a veterinarian. I am sorry to hear about your fellow's intermittent episodes of vomiting. While drinking water that has a higher than usual bacteria content due to his housemate's poor oral health isn't good for him if this were the only problem I would expect consistent vomiting, as he is exposed to the water daily. I think that there is more than just contaminated water involved.In many cases intermittent vomiting is triggered by eating something they should not, too much table food, too many treats
or something they find outdoors, esophageal reflux, or a dietary allergy or sensitivity.More serious causes of intermittent vomiting include chronic pancreatitis
, inflammatory bowel disease, internal organ failure (kidney or liver disease), a partial gastrointestinal obstruction or even infiltrative cancers such as lymphoma
or Addison's disease (hypoadrenocorticism). Rarely a parasite called a stomach
worm (Physaloptera) can lead to intermittent vomiting. These are difficult to diagnose because they rarely shed eggs
, so we can try simply worming him with a gentle wormer called Pyrantel and see if that helps. This is easy to do and inexpensive so well worth trying. If that doesn't work and since he seems to feel well otherwise some dogs seem to vomit more on an empty stomach so feeding
him small meals several times a day, and maybe a snack before bedtime, may be very helpful.It may also be helpful to put him on an acid reducing medication as too much stomach acid, especially on an empty stomach, is very irritating and predisposes to vomiting.I recommend giving him a dose before bed so that it is in his system in the morning. You can give either: 1) Pepcid ac (famotidine
) at ¼ of a 10mg tablet per 5 to 10 pounds of body weight every 12 hours OR 2) Prilosec (omeprazole) at ¼ of a 10mg tablet per 5 to 10 pounds of body weight every 24 hours These are both acid reducers and should help him feel better. They are quite safe and can be used long term if necessary. You might also consider feeding a low residue, low irritant easy to digest food. Both Science Diet and Royal Canin make sensitive stomach formulas you can find at the pet store. If he continues to vomit even with the acid reducers, runs a fever (more than 103F rectally), has a tense painful belly or if he refuses to eat he should see a veterinarian for an examination, and some diagnostic testing. I would start with a complete blood count and biochemistry profile, a specific test for pancreatitis called canine specific pancreatic lipase, as well as fecal checks for parasites.Please let me know if you have other details or a particular question based upon my response.