Puppies and worms

Question
have an appt at vet tomorrow but ,we"rescued" a 5 month old male 5/16 from friends tenant that couldn't take on move. Was wormed prior to us picking him up, the day of his1st vet visit passed stool with many worms.identified as Roundworm and we have gone through 3 rounds of vet de-worming.Past 2 days worms in stool again is this common that treatment needs to be repeated so often?

Answer
Treatment for worms is a multiple-dose process; you're seeing the worms in his stool because the medication is working.  Sometimes puppies with a heavy load of worms need a couple rounds of medication before they're parasite-free.  You also want to be sure to be meticulous about keeping the stool picked up in the yard - otherwise he could keep reinfecting himself.

Good luck!