A little background history... we rescued an adult cat who was being fostered. There was no medical history, all we knew as it had "allergies" and that it wasn't gaining any weight (skin and bones!). It was a pure bred Tonkinese female and I quickly suspected it was ill. I got it to my vet quickly to discover it not only had an upper respiratory infection, but hyperthyroidism and it was older than first suspected. Why the foster "parent" never had any blood work done on a senior cat with no medical history is beyond me, but at least I save a life. Anyway, after a bout of pancreatitis from the stress of moving her, and on top of that, into a home with 8 other cats, we were able to start giving her the thyroid pills. At first, she gobbled up the cream cheese "treats" and everyone was happy, then 2 days later, cream cheese gone, little pink pill is on the floor... next step, pry open mouth, pop down throat, hold mouth shut until she swallows. Wise cat, she won't swallow, spits pill out. Next step, pry open mouth. pop down throat, hold mouth shut, get plastic syringe with water and put water down her throat several times. Unfortunately, in the time it took too get the water, she had time to hide the pill and spit it out after a few bouts of water! Clearly, she's taken pills before! That's when I went hunting for these so called pill guns. This one looked the best, because it had the water and on occasion, the water trick did work, just not always. So, did it work? Yes, it works! Let's start with what not to do. 1. Do not put it the side of the cats mouth. While this works for liquid medications, it doesn't work for this. This seems to leak a lot of the water out, thus not giving the full amount and leaving room for wise cats to still be able to spit the pill out. Lesson learned. 2. Do not do this slowly, thinking it's "nicer" for the cat, this allows for them to be able to separate pill from water and spit the pill out. Again, lesson learned. Now, let's talk about the correct way to to do it. 1. Fill the entire barrel with water (as far as it will let you, which is not all the way). 2. Wedge the pill in the tip, it's perfect for thyroid pills! 3. Place about half of the white part (see picture) into the FRONT of the cats mouth (see above, not the side!) and QUICKLY (see above, not slowly) push down and administer the water/pill as quickly as possible. This may seem like you are going to gag your cat on water, but trust me, you don't. They swallow very quickly and they don't have time to react to the surge of water and the pill mixed in with it, thus they can't sort pill from water and they have to swallow it. Note: They will be peeved. Probably for hours. They may bite, hiss, scratch, and hold a grudge for who knows how long. They may put a 21 pound cat in their place w/in minutes of having received said pill - yes, this has happened and it was quite comical. They may in fact hiss at every cat (And human) they come in contact with an refuse treats just to spite themselves. However, beware, as every other cat in your house will expect a treat just for putting up with the madness of the now peeved cat. You were warned. I highly recommend this product if you have a pill spitting cat! However, I will say that I don't know if a large pill would fit in the tip.