Parasite control broadly comes in two kinds — internal and external, depending on whether it targets internal or external parasites. It can also be done with combined products that act against both.
Internal deworming:
In dogs and cats the first deworming can be done from 3 weeks of age, repeated twice more at 14-day intervals (three times in total, 14 days apart). After that the schedule is 4–6 times a year — every 2 or 3 months, depending on your pet’s environment. If the animal lives outdoors, spends much of its time outside or goes hunting, every 2 months is recommended. Internal deworming is most often done with tablets, but for animals that are difficult to give pills to, it can be replaced with a syrup, paste, or a spot-on emulsion applied to the skin, which is absorbed through the skin into the bloodstream and kills the internal parasites.
External parasite treatment:
Its aim is to destroy all parasites on the skin and coat. It can be done with powder, a bathing solution, antiparasitic collars, spot-on pipettes applied to the skin, or oral tablets — the latter are very suitable for animals with allergic reactions to external products, and also when extra safety is needed around small children, avoiding any chance of them swallowing part of the external product or handling your pet’s antiparasitic collar.
Parasite control in exotic animals is also internal and external. The most convenient way is with combined spot-on products applied to the skin that act against both internal and external parasites. The schedules vary and depend on the species, its contact with the outdoor environment, and the food it eats.