We use Tri-X Heartworm pills (apparently taste like treat - we hide them and she finds them. We also use the generic FrontlinePlus for fleas and ticks - that's the stuff in the little squeezepacket you use once a month.
She also gets Denamarin for some sort of a kidney issue. To me, it smells the same as the heartworm pill, but pill pockets, peanut butter, sliced chicken just get her to spit it out and we have to shove it down her throat - hard because she gets two at a time daily.
The only thing that disguises it is if I hide them in a half of a BabyBel (those cheese things in the red wax) - cut it in half, dig a hole in it, stuff the pill in and squish it shut.