Dog is paying a lot of attention to its bottom - dog walker says they've seen what appear to be worms in the stool. Do I need to bring 'it' in for inspection to determine the type of worm, or is the medicine generic enough to treat all types?

Yes, bring in a sample. Revolution is an excellent flea, tick, and also certain types of parasite , worms, mites. St. John's is the best vet ! Good luck

I agree with others, take in a sample.

Yes bring a sample, plus the anal glands may be plugged.

I would bring in a sample of it.

I would bring a sample to the vet.