The acronyms for Hill’s Prescription Diet foods are not difficult to figure out. The “d” always stands for diet. It was easy in the old days, before there were so many different Prescription Diets. c/d was “crystal diet,” k/d was “kidney diet,” and h/d was “heart diet.” If memory serves me correctly, when I graduated in 1980, that’s all the diets there were.

Now, few letters go unused.
b/d is for “brain diet,” and contains ingredients that help dogs who have dementia problems, especially from liver disease and old age.
The nutritionists at Hill’s figured out that not only could struvite problems be solved in cats by feeding a special diet, a dog-formulated diet would work for canines, too. Canine c/d was born, and the “c” still stands for “crystal.” Click here for explanation of struvite.
d/d is for “dermatology diet,” and there are several formulations for patients who need a special diet for food allergy. d/d can also be helpful for certain gastrointestinal problems.
g/d is for “geriatric diet” and is also used in certain cardiovascular and kidney diseases.
h/d is for “heart diet” and is formulated with low sodium for patients with cardiac problems.
i/d stands for “intestinal diet” and is effective for patients with a variety of gastrointestinal problems. It is highly digestible, making it ideal for pets with “sensitive stomachs,” and low-residue, so it’s excellent for constipation problems because less total stool is generated.
j/d is one of the newer foods and is formulated with neutraceuticals to enhance joint health through stronger cartilage.
k/d was Dr. Mark Morris’ very first food formulated, though, of course, new formulations have been created as research reveals more and better ways to care for patients with a variety of kidney diseases.
l/d is for “liver diet” and contains ingredients to help with a variety of liver problems including cirrhosis and copper storage diseases.
m/d is a feline-only formulation that is Hill’s lowest-carbohydrate food. It is the diet of choice for diabetics and cats with obstipation.
n/d stands for “neoplasia diet,” and is “clinically proven to increase survival time and improve quality of life for dogs with cancer undergoing chemotherapy or radiation treatment.” [Hill’s Key To Clinical Nutrition.]
r/d is one of Hill’s biggest-selling Prescription Diets because, as in people, obesity is epidemic in animals. Reducing diet is high in fiber, yet low in calories, so pets get to have a large meal, keeping them full, while also gradually taking weight off.
s/d is a “stone-dissolving diet,” discussed in detail in an earlier article.
t/d stands for “tooth diet” because its formulation and physical characteristics are both special. The formulation contributes less to the physical and chemical components of plaque. Also, fibers are laid into the food that squeegee each tooth that bites into the food.
u/d can non-specifically be called “urinary diet,” but it’s actually a food for pets whose kidney failure has progressed to an extreme level. However, u/d is also helpful for dogs predisposed to calcium oxalate urinary bladder stones.
w/d is kin to r/d in that it is a “weight-control diet.” w/d, though, is for dogs and cats who have lost the weight and are now ready for a maintenance food. It is high in fiber, but not as low in calories as r/d. It is also fairly low in carbohydrates and is often used in canine and feline diabetes.
x/d is a feline-only food designed to prevent calcium oxalate bladder stones in cats.
y/d is also feline-only, and is used for controlling hyperthyroidism in cats.
z/d (you thought we’d never get there!) gets its “z” from hydrolyzate. Proteins an immune system has never seen are needed for food allergy patients. It is also unique in that its proteins are hydrolyzed, making it difficult for a food-allergy-primed immune system to respond to them.
There you have it, the entire Hill’s Prescription Diet alphabet soup.
Aren’t you glad Hill’s Science Diets just have regular names?
Hi my dog eat hills ID Low fat prescription diet , but she gets bored and is very difficult to make her eat . Is there’s any other maybe a wet food that I can mix it with ??
Your baby is on i/d low fat because of SOME kind of digestive problem. THAT’S why it’s “very difficult to make her eat.” Dogs & cats don’t get tired of foods like people & they don’t need variety IF they’re on a quality food such as Hill’s Pet Nutrition. i/d comes in regular canned & canned stew. Thanks for reading, Dr. Randolph.
Is id low fat wet food the same as id digestive care,as my dog has pancreatitis
i/d Low Fat is lower in fat calories than “regular” i/d. IF your attending veterinarian recommends it, it MAY be a good choice to help with your dog’s pancreatitis. Thanks for reading, Dr. Randolph.
hi! i can’t find it on your other post about a/d, but what does the A actually stand for? thanks!
I don’t think it “stands” for anything. It can be used for dogs AND cats, so, maybe it stands for “anybody.” I believe it was a letter they hadn’t used when they formulated it and it worked. And, it’s at the beginning of the alphabet. Thanks for reading, Dr. Randolph.
Which is the better good to break up bladder stones, u/d or c/d?
It depends completely on the type of stone. One size does NOT fit all. u/d may help dissolve urate and cystine stones. c/d can be used in the management of struvite stones. Thanks for reading, Dr. Randolph.
Hello,
Thank you for the alphabet meanings, very helpful.
Seeking info about the following:
z/a
h/a
h/p
Unless I missed them, would be great to know.
Thanks
Mark
Hill’s Pet Nutrition codes all end in “d.” If the food doesn’t have a “/d” code, it has a name. Thanks for reading, Dr. Randolph.