Well what I did for my dog was went to the farmacia and asked for parasite medicina para ninos! and thats what my vet said would work and he is right it does! If your dog is outside alot do it every 6 months! Also keep an eye on their gums, if they start to lighten or go yellow or white, take him to a vet IMMEDIATELY, because of the poison on teh streets, have lost 5 animals to poisoning! Some are worse than others ... if when they have bowel movements its mixed with blood dont ignore it as well as throwing up go to a vet asap ...on the north coast, i recommend Dr. BOB!
Gata!