Yes to fresh pineapple, in genuinely small pieces
Your puppy can eat pineapple, and its bright, tangy sweetness makes it a high-interest treat for puppies who have grown bored of their usual rewards. The fruit that reaches her, though, must be only the soft yellow flesh. Cut away the spiky rind entirely, remove the hard central core in full, and then cut the remaining flesh into small pieces matched to her size. Offer two or three pieces, not a ring, not a spear, and not a bowlful. Fresh pineapple at that scale is a fine occasional treat.
Core and rind: the parts that never get served
A pineapple's core is woody, dense, and fibrous — nothing like the juicy flesh around it. A puppy chewing a piece with core attached can work a hard lump free and try to swallow it, and fibrous core material is also tough for a young digestive system to break down even when it does go down safely. The rind is worse: tough, sharp-edged, and covered in spines that can scratch a mouth and throat. Neither part should ever be given as a chew, dropped into the bowl as a garnish, or left in a fruit-scrap dish a puppy can raid.
Sugar, acid, and the enzyme in the flesh
Pineapple is one of the sweeter fruits a puppy might meet, and it is noticeably acidic, so portions protect her stomach as much as her waistline. Too many pieces commonly produce a loose stool, sometimes with a bout of wind or a puppy who is slightly off her next meal. The flesh also contains bromelain, an enzyme that breaks down protein — part of why pineapple tenderizes meat — and while the amount in a few pieces is no concern for a healthy puppy, it is one more reason a whole bowl is a bad idea for a small, still-developing digestive system.
Fresh and frozen yes, canned in syrup no
Canned pineapple is packed in syrup or sweetened juice, and that liquid turns a measured treat into a sugar course — skip it, including the tidbits and crushed varieties, which are the easiest of all to over-serve by the spoonful. Fresh is the standard. Plain frozen pineapple pieces, frozen at home from fresh flesh you have cored yourself, make an excellent warm-weather variation: the cold slows a fast eater down and soothes a teething mouth.
Puppies, pineapple, and the coprophagia question
Pineapple has a folk reputation you may meet in puppy groups: feeding a dog pineapple is said to make her stool taste unpleasant and so discourage puppies who eat their own droppings. The evidence for it is thin and anecdotal, and it is not a reason to feed pineapple in quantities beyond treat size. If your puppy is eating stool, the reliable responses are prompt cleanup so there is nothing to eat, supervision in the garden, and a word with your veterinarian to rule out a dietary gap or digestive issue — especially in a growing puppy.
When pineapple should prompt a vet call
Get prompt veterinary advice if your puppy swallows a piece of rind or a chunk of core and then coughs, gags, retches, drools, or goes off her food, and call the same day if she raids the fruit bowl or bin and eats a large amount of pineapple in any form, since the sugar and acid load can leave a small puppy significantly unwell. Repeated vomiting, watery diarrhea beyond a day, or unusual tiredness after any fruit feast also deserves a call rather than another day of waiting. And because helpers often serve the fruit salad version — mixed sweetened fruit, core and all — note pineapple clearly as fresh flesh only, core and rind removed, in KinsLe through Care Teams, so anyone treating your puppy serves the safe cut you prepared.