I agree with Misfits4me, have his teeth checked. We found a cat two years ago, and his breath was horrible. The first time his teeth were checked they removed all but 10, yesterday they had to remove the rest. Have your dog checked before they get this bad.
Hello & welcome....Poodles (Toy Breeds) are notorious for Dental Disease.....Has he ever had a Dental? If Not, that's where you need to start.....Make an appointment with your Vet to have his teeth cleaned....They will be able to take care of any rotten/abcessed teeth & give an antibiotic for any infection.....
Trust me, if left untreated, the bacteria from dental infection can enter his bloodstream and create all kinds of damage....The worst IMO, is Heart Disease!
Untreated, can also lead to such severe pain, that a dog will quit eating...That's clearly trouble, also....
After you have this done, stay on top of brushing (With a doggie toothpaste) his teeth at least 4 times a week.....Also, there's a spray/gel called "Petzlife" that works wonders for killing bacteria in the mouth....But Please, have his teeth cleaned first and start with a clean slate......Good luck and let me know what happens......Karla