Cats are very smart animals, and they learn quickly how to avoid unpleasant aspects of their lives. Taking medicine is usually one of these unpleasant things they must endure. The problem is that many feline medicines are really only scaled-down versions of people medicine; therefore, they're usually flavored for people, not cats. As a result, most cats are not too willing to swallow something like this. Sometimes you need some strategy to give kitty his medicine.
Be careful not to frighten the cat when you approach it for the first time with medicine, as this will cause the animal to fear medicine from that moment on. Approach quietly and naturally as you always do.
If the medicine is in pill form, try shooting it down the cat's throat with a specially designed pill shooter. This will require some practice to keep the cat from spitting it back out 20 times before you finally get it down its throat. Gently grab the cat from behind, slip a hand under its chin and raise the head. Slip the pill shooter between the cat's jaws as far back into the mouth as you can without gagging the cat and shoot. The pill should go right down, but clamp the cat's jaws shut immediately to keep it from spitting the pill back up.
Giving a cat a pill that it doesn't want is one challenge. Giving the same cat a "tasty" orange-flavored liquid medication is quite another. This is tantamount to force-feeding liver-flavored medicine to your young children, for the reaction is very similar. Cats do not like oranges, and this medicine is disgusting to the cat's sense of taste. You will need a small eyedropper to shoot the liquid into the cat's mouth. The easiest method is to get behind the cat, stick the tip of the eyedropper into the side of its mouth and shoot as quickly as possible toward the back of the throat. You will, no doubt, slop a little of it all over the cat, and whatever surface it is sitting on at the time.
The cat will dislike this activity with a passion and will fight you, which is why it is a good idea to get behind the cat with an arm around its neck to hold its head up. The cat will do everything in its power to avoid that medicine, so a little restraint is a good thing to get the job done. The cat will even drool in order to avoid swallowing the vile stuff, so don't be surprised to see colored rivulets running down both sides of your cat's mouth. You can prevent this by continuing to hold the cat's head up and stroking its throat until it swallows.
Some cats take medicine really well. In fact, many will actually chew a pill or happily lap up liquid medicine. If you have a cat such as this, the technique is different and will be much simpler. Put the pill into the cat's food or simply toss it to the cat, and it will eat it. Same thing with liquid medicine: Put some into the cat food.