Dog's breath smells terrible — when is it normal and when is it a health problem?

For a 5-year-old Golden, bad breath is almost certainly dental tartar unless there are other symptoms. "Teeth look okay" is a pretty superficial assessment — you really need a vet who can assess plaque buildup under the gum line, which requires proper examination (and ideally X-rays for older dogs).

Push for a dental scaling under anaesthesia if the tartar is significant. Yes, general anaesthesia has risks, but dental disease in dogs causes bacterial spread to heart and kidneys if untreated — it's a much bigger health risk than the procedure.

Smell profile matters for diagnosis. Garbage/rotting smell = almost always dental (anaerobic bacteria under gum line). Sweet/fruity smell = possible diabetes or metabolic issue, worth a blood test. Ammonia/urine smell = kidney disease flag, urgent vet visit. "Fishy" or foul-but-different = could be anal gland issue (you'll also notice butt-scooting). Based on what you've described, dental is by far the most likely.

For actual dental vets in India: look for a vet with "dental scaling" listed as a service and ask specifically if they have dental X-ray capability (called dental radiography). Major cities have specialists — in Bangalore try Cessna Lifeline, in Mumbai try Bombay Veterinary College or IndiVet. A good dental clean costs ₹3000-8000 depending on the city and extent of tartar.

Daily brushing with a dog toothbrush and enzymatic toothpaste (NOT human toothpaste) genuinely prevents buildup. It's hard to start with a 5-year-old who's never had it done but a soft finger brush with chicken-flavoured toothpaste can win over most dogs within a week. Even 3x per week makes a measurable difference.

Rawhide chews are controversial — some studies show they contribute more to dental issues than they help. Look for Whimzees or Greenies dental chews instead, which are specifically designed for tartar control and are digestible. Given daily they can visibly reduce plaque over a month.

Our Golden had the same issue at age 4. Full dental under anaesthesia removed 11 teeth (most already loose from disease — we had no idea). Butter will almost certainly need at least a scaling. Don't delay it — gum disease progresses quickly once established.

Get a blood panel done alongside the dental assessment — especially BUN and creatinine for kidney function. At 5 years old, it's reasonable to have a full baseline. If the bad breath has a kidney component, it will show up there. But again, dental disease is by far the most common cause of what you're describing.