Hill’s Prescription Diet Z/D Canine (Dry)


Rating: ☆☆☆☆☆

Hill’s Prescription Diet Z/D dry dog food is not rated due to its intentional therapeutic design.

Notes and Updates

07/19/2010 Original review
05/09/2012 Review updated
11/14/2013 Last Update

  • Chip Bridges

    Purina is NOT a great food. Just look it up on this website!

  • jackc

    It’s been a month and the food switching to Origen Sr has been going well. She is getting about 80% Origen at this point and we have seen no adverse effects. My feeling is he will probably get her weaned from ZD in a couple of weeks. I have to assume that her problem may have been grain oriented since ZD and Origen both contain no wheat or corn products. Her weight is down a little and she looks more trim at this point, Being a Golden Retriever/Beagle mix we noticed that her frame is larger than his other dog of the same size that is Britney Spaniel/Beagle.

    I talked to the folks at Origen earlier about putting or the senior food even though she was a year and a half old. They assured me that the protein content was very adequate for a dog her age and once we got her weight down, we could increase her intake based on her activity.


  • jackc

    Well it has been just over a month and my son is now feeding the ratio of about 80% Origen Senior and 20% ZD. No sign of the food allergy previously seen by the foster family. We don’t know what they were feeding her prior to them going to ZD, but Origen seems to not include what was triggering her problems. I have a feeling it may have been a grain issue.


  • InkedMarie

    Put the kibble on a cookie sheet.

  • sue66

    Yes I’ve tried the muffin tray, I order the a bowl on E-bay & there’s 6 rounded plastic things that stick up, 3 are small & 3 are big, 3 of the big plastic things that are sticking up seem to be too to high & too close, his nose is too big & cant get the kibbles, so he gulps more air licking & trying to get his kibble, Whats the cookie sheet???

  • InkedMarie

    If he’s eating too fast, you can buy a Brake-fast bowl, use a toy designed for food, use a muffin tin or use a cookie sheet.

  • aimee

    It is unreliable in my opinion. If the mechanisms of Adverse Food Reactions are unknown than how can there be a test developed to accurately test for them?

    To add to that I recently learned that a vet sent tap water in and it tested positive for a variety of foods. Has the test been “fixed” since then?? Who knows! But it sure makes you wonder.

    I think people of possible AFR dogs are better off spending their money on a well done food trial than on a test.

  • aimee

    Hi madeinmiami,

    I’m not sure if you are looking for data to support the statement by Dr Hnilica or for my statement on Nutriscan. I’ll address both options.

    There aren’t any third party peer reviewed papers published on the reliability of Nutriscan. At least I can’t find any. I didn’t come across anything on salivary testing in regards to AFR in dogs either but it may well be out there.

    Do you know of any data showing the test is accurate?

    Practically speaking though, since the mechanism/s of Adverse Food Reactions in the dog are not well understood I don’t see how there can possibly be a method by which to test for them.

    I did learn of some data generated in regards to Nutriscan. It is unpublished and at the time the tests were run Nutriscan did not fair well.

    If you are looking for data regarding food testing in general you can find summaries of three data based studies here: http://dermvettacoma.com/pitfalls_otc_blood_allergy.pdf

    Or if you want to read original peer reviewed data based studies here are some to get you started: Schweiz Arch Tierheilkd 2005, Jackson et al 2003, Mueller Tsohalis 2002, Foster et al 2002, 2003, Jeffers 1991, Halliwell et al 2004, Bethleham et al 2012

    r you can simply look at what the companies that run such tests say about their own tests: “Heska, in agreement with the American College of Veterinary Dermatology, does not recommend IgE testing for foods. A compliant exclusionary diet trial, followed by provocative re-challenge, is recommended for animals
    suspected of suffering from adverse reaction to foods.”


    P.S. I have never said “Purina is a great food.”

  • theBCnut

    I wouldn’t use the capsule for acid reflux anyways, since you want the acid delivered to the top of the stomach, however they would be great for all the other benefits of ACV.

  • theBCnut

    My dentist has the same complaint!! He makes up for it with my husband though, but my kids inheritted my teeth. TeeHee.

  • theBCnut

    I’m not sure if it would matter other than the vinegar might not be enough to work if the Zantac acts to neutralize it.

  • theBCnut

    I do clean with vinegar, but not the same vinegar I drink!!

  • http://www.dfwpugs.com/ sandy

    I take the capsules but am thinking about ordering the 200 mg ones for the dogs when needed since they take capsules well and for when I don’t use the liquid from the bottle. Tonight I’m making dehydrated food so I’m adding in the liquid.

  • Bobby dog

    Thank you so much for the link! I am trying to convince my mom to start taking ACV for some health issues she has and she makes a “yucky” face when I mention it. This will be perfect for her because she is interested in trying ACV.

  • sue66

    I just looked at the books that I borrowed yesterday from the library & I’ve borrowed “Bragg” Apple Cider Vingegar Miracle health system.. I must of seen it somewhere on the net & have borrowed it, I just dont like the fact that u can clean with it then drink it..YUK

  • Bobby dog

    Thanks for the info! Luckily when I take ACV I am at home so I will change my routine. My dentist always jokes with me that he doesn’t make money from my visits. I have only used ACV for indegestion for a few years, and not too often. But thanks again for passing your knowledge my way!

  • Betsy Greer

    Should she also stop giving him the Zantac when she starts the ACV?

  • http://www.dfwpugs.com/ sandy
  • theBCnut

    It doesn’t matter if you give it after his meal in a syringe. You want to give 2 1/2ml of ACV and 2 1/2ml of water, mixed together for every cup of food. You can mix it up ahead of time and keep it in a jar, just do half ACV and half water.

  • Bobby dog

    That’s funny, I remember those commercials, and maybe they still show them? There’s always a caveat with everything isn’t there!

  • sue66

    Do u give the capsules to ur dog or is it for urself??

  • sue66

    I cant ad to Patches kibble as I hand feed to slow him down & to make sure he chews all his kibbles, If I put in a bowl he will just gulp & swollow 1 cup of his kibble in 4-6sec.all un chewed, at the moment he’s doing his swollowing & swollowing & licking, he ate over 1/2 cup of his new & old kibble at 9am then about 1 hour later the licking & swollowing starts he just ate some grass,the acid went away since he been on Zantac but since starting this new kibble 1 & half weeks ago the swollowing has started as I increase the new kibble with the old..I think this new kibble has something in it that irritates his tummy what ashame, his poos were excellent & there was no farting… I’d like to make up some apple cider vinegar & give him about 1 teaspoon to releave his acid but do I do half apple cider & water or 1/3 apple cider & water how much would I mix to give him 5mls worth like when we take Mylanta {Pepto} I often just take 5mls, I was giving him 5mls of mylanta but one nite he ended up having diarrhea after taken the Mylanta, so I’ve never given it to him again..

  • theBCnut

    I wonder how toxic those enamel restoring mouthwashes are.

  • theBCnut

    Don’t do this!! It takes 30 minutes after exposure to acids for your tooth enamel to reharden and brushing can damage your tooth enamel during this time. Dilute the ACV with equal parts water, then as soon as the heartburn starts to subside rinse and swallow more water if you like, but wait 30 minutes or more before brushing or eating hard or crunchy foods.

  • Betsy Greer

    That reminds me of those Sensodyne toothpaste commercials where the dentist talks about acid erosion caused by brushing too soon after eating / drinking acidic foods. I bet the extra water chaser is a good idea though.

    I bet Dr. Mike could tell us about this!

  • Bobby dog

    I believe it, I am very careful. I chase it with a glass of H2O then I brush my teeth. Luckily I don’t eat hot wings often! I suppose the same consideration should be taken if drinking Braggs’ ACV drinks too; you never know!

  • InkedMarie

    Betsy, check your email.

  • theBCnut

    I can chug down pickle juice, but drinking ACV is right out. I’m going to have to look for those capsules too. My dad drinks his ACV in lemonade, but I’m not sure if that defeats the purpose.

  • Betsy Greer

    Just be careful! I got a bottle of Bragg’s for my elderly father. He got into the daily habit of drinking a bit diluted in a glass of water. At his next dentist appointment, he had a bunch of very strange little tiny cavities on the surface of his teeth. That was an extremely expensive trip to the dentist. I felt horrible. : (

  • Bobby dog

    I did not know there were capsules! Bragg is the brand I use and I did not know they made ACV drinks, I am going to check it out. I actually like the taste of ACV so a small teaspoon is no big deal for me. I just need to learn when to stop eating hot wings!

  • Betsy Greer

    Try a teaspoon diluted with at least that much water added to his food at mealtime.

    ACV stimulates the production of hydrochloric acid and tells the spinchter to close and therefore, not send more acid than required for digestion into the stomach. I know I’ve heard some folks here say that the use of proton pump inhibitors can actually be counterproductive.

    Try it! You might see a difference pretty quickly.

    Here are some good WDJ articles about raw, unfiltered ACV with the “mother.”



  • http://www.dfwpugs.com/ sandy

    I buy ACV capsules! I tried making a drink out of the ACV but couldn’t get it down. Although I actually like Bragg ACV drinks.

  • theBCnut

    Acid reflux is not usually due to too much acid production, actually just the opposite. The sphincter muscle at the top of the stomach closes because it detects acidity. Older dogs and older people sometimes produce less acid, so this muscle doesn’t close as tightly as you would wish. When I have issues I take a swig of dill pickle juice and it clears it up immediately. My dog that has this issue get ACV in his food, 1/2 teaspoon per cup of food. No more problems in well over 1 1/2 years. Adding water helps too because protein and water combined tell the stomach to release more stomach acids.

  • Bobby dog

    Hi Sue66:
    I give ACV to my dog at every meal to help with his intermittent indigestion. It is important to dilute the ACV with water so the enamel on his teeth is not damaged. I also take a small spoonful of ACV when I have indigestion (from eating too many hot wings).

  • sue66

    Just Google ACV Apple Cider Vinger I looked into this but was a bit worried it being a acidaty product maybe making his reflux worse… instead of putting with food how else can I give it to him & how much do u give him hes 17kilos, he gets a third of a Zantac half a hour before his 9am feed & at 8pm at night but I think I need something stronger, last yr I tried Losec 20mg but I think the 20mg was too strong as he was acting weird, flinching, just starring at things on the second day, so I stopped the Losec, I was going to ask the vet for 10 mg losec & see if he still has a reaction, I dont know what else they give dogs with stomach acid, does anyone know..

  • sue66

    What is ACV??? my last rescue dog never had any problems only the last 2 yrs of her life ..this last yr, I seem to live at the vets with this new rescue.

  • Betsy Greer

    Hi Sue66,

    Have you ever tried adding diluted ACV to your pup’s food?

  • madeinmiami

    Your article has no data to support the statement –

    “3. Food allergy testing (intradermal, serologic): not recommended because test results are unreliable. Some dogs will have positive reactions to storage mite antigens, which may be clinically relevant, or they may exhibit cross-reactivity with other insects. Storage mites are ubiquitous, and their clinical significance is currently unknown.”

    Id lump your comment in with some of your other questionable opinions like Purina is a great dog food.

  • sue66

    They’re called Furuncles, I have a English Staffy u can see boof head in photo, he too gets those blood fillled sores inbetween manly back toes, he’s got 1 at the momnet, I put Detol Antiseptic cream & it starts to heal quicker within 1-3days, the vets gave me Apex Antibiotic lotion with Hydrocortisone & Lignocaine, but this cream seems to take longer to heal, they’re a Bacterial infection sometimes I’ll sook Patches feet in Detol Antiseptic in cold water if I start to see him lick them also Malaseb medicated shampoo is excellent for skin & feet.. Im starting to feed my boy Nutro Chicken & rice but Im in Australia different ingredients its like the American LID it only has Chicken, grounded rice & dried pulp beet, chicken fat, But Patch was put on the Eukanuba Intestinal for his tummy last August this has worked excellent, this is his first Furuncle & summer is over, last year we were getting a new Furuncle as soon as one healed so the Eukanuba Intestinal must be fixing something Im only starting to change his kibble cause he has Acid reflux I thought maybe the food but he’s been getting it a bit worse since slowely changing to the Nutro maybe the Rosemary extract in the kibble..Google Interdigital Furunculosis.. Good Luck with ur boy

  • Amy

    Why is the nutriscan test unreliable?

  • aimee

    I’d lump the nutriscan test in with the rest as being totally unreliable.

  • Shawna

    Hi Chrissy,

    I agree with dchassett that allergy testing is not very accurate — false positives and false negatives. Actually, allergy testing is not even that accurate in humans. My M.D., who is also a Certified Clinical Nutritionist, had me do an elimination diet to determine the food I was reacting to — (dairy for me).

    Like USA said, food intolerances (or sensitivities) are far more common and would not show on an allergy test even if they were accurate.

    Symptoms of intolerances can manifest in MANY different ways — diarrhea, anal gland issues, itching, colitis/IBD, arthritis, aggression, ear problems, eye discharge/staining, coughing and more.

    It’s best to put him on an elimination diet. Feed him a food (protein and carb source) he hasn’t had before. If you can feed a balanced home cooked or commercial product (like dehydrated or freeze dried) you might have a better chance. It is important to change both the protein AND the carb as the carb is often the problem — potatoes, legumes, peas, grains etc. Sorry if this has already been mentioned.

  • dchassett

    I have a dog with many food intolerances and allergies and even her Allergist will not do the test because he told me it’s truly a waste of money because allergy testing in dogs is not accurate as testing in humans. He said that having a dog with allergies and intolerances is costly enough without taking money from clients who are trying to help their animals when he knows the tests are inaccurate. The only real way to deal with these issues is process of illumination. In my case, I switched her to a grain, soy, white potato, white rice, poultry (all types of poultry) free food. She is by no means completely free of problems but that is also because she has environmental allergies. She does best on commercial raw foods. Katie came to me in this condition at the age of 9 weeks old. She is now 4 1/2 years old and it took me years to slowly figure out and eliminate different things from her diet. Oh, she also cannot tolerate synthetic vitamins, or any type of unnecessary additives in foods including flavorings, dyes, etc. If any vet tells you that food allergy testing for animals is accurate they are just taking your money. Also my traditional vet will not do food allergy testing for the same reason that the allergist won’t. They are expensive and inaccurate.

  • USA Dog Treats

    Hi Chrissy,

    This is from


    “Do you often hear or say “allergies”? More than likely, you are referring to a food intolerance or sensitivity, which is actually quite common. An actual food allergy is rare. In fact, food intolerance is the third most common sensitivity condition in dogs and cats, and often was remedied with a change in diet. For years, though, the difficulty lay in figuring out what foods were problematic – until now.”

  • dchassett

    Hi Chrissy. What food is your guy eating presently? Let’s start there and see if we can figure things out? Also you says he suffers from allergies for the better part of his life, what are the things you know and/or suspect he’s allergic to?

  • Beth Knuth

    what about raw, Darwin’s especially, delivered right to your door, frozen and well made. Visit their web site and call them, they help you all the way through. I was feeding my Butch, pit bull, one meal a day, but I am going to go full time, he just doesn’t do well with kibble. He vomits it up once in a while, the kibble, not the raw. Good luck to you and your beloved pup.

  • aimee

    Hi Chrissy,
    Food Allergy tests are completely unreliable in determining what it is a dog is reacting to.


  • Chrissy

    Also none of the prior comments that I read talked about any symptoms like my guy suffers from at all. With the pimples in between the toes and face some times. They were GI related…I think that is something else for me to really be aware of and check into.

  • Chrissy

    jweejwee…thanks for your story..so glad it ended well cause I was holding my breath. I have to say, there was so much I got from what you wrote, one of them being get ‘Pet Insurance’. After reading yours and some other comments it seems that the ‘food allergy’ can raise its ugly head in so many different symptoms. And what I am gathering is that the best route is to have the blood panel done now and hope to pin point exactly what ingredient he is allergic to. Now I have had dogs my entire life and have never had to deal with an allergy problem. If I spend the money to do the test, how accurate can they get as far as telling me exactly what he can not have in his diet….?

  • Betsy Greer

    Thanks for sharing, Joanne. I kept thinking, 29o

  • jweejwee


    Sorry this is so lengthy, but I just want to share some things that may help others care for their “best friend”…..Keep in mind, this is strictly based on our personal experience…..

    3 yrs ago, after 4 years of working with Vets finding the source of our Golden-doodles’ GI problems; uncontrolled explosive diarrhea, excessive gas, bloating, projectile regurgitation and spitting up water; we tried Z/D Ultra diet and medications. His symptoms flared up only intermittently….for a while anyway…Until finally turned critically ill…one evening, we found him in a pool of bright red blood and clots he had vomited up… He was admitted to ICU for 3 nights and unbeknownst to us, in a lot of pain..…besides the vomiting, he had little change, he was still vibrant, happy, loving self…..except more needy and a change in appetite….sadly, we missed the signs of a “very sick dog”……..After 3 nights in ICU, extensive testing, blood work, an ultrasound, he had a diagnosis: “Acute Pancreatitis, Inflammatory Bowel Syndrome and Severe Dehydration.”

    In hindsight, his appetite decreased over 2 days, then stopped, nosing his food, (unusual for our voracious eater); he was smacking his lips, very anxious and pacing; we knew he was not feeling well but attributed this to being “very needy”, “separation anxiety” and very “high strung”; a diagnosis given to him as a puppy….none of which were correct….I suspected Allergies….(you know, stomach aches in people…)

    He was sent home on numerous medications including Prednisone and Z/D Ultra; put on 20 lb. (normally 58 lb. ), could barely walk 1 block….although no vomiting or diarrhea, the medication side effects were taking a toll on him…if in 30 days he wasn’t better, they would do an upper and lower GI “Scope”, look at his GI tract and do biopsies. They were thinking allergies, but weren’t really sure…so we were going to wait out 30 days. When we tried to wean him off Prednisone, his GI problems returned…they wanted to add a Cancer medication to his treatments….OR…..do the scopes. We chose the scope….

    The vet couldn’t believe it…his stomach and large intestines were perfect, but his small bowel was so inflamed that when the scope was passing down, brushing the side walls, it would bleed…by just touching it, no biopsy!!! His entire small bowel-extremely inflamed and chronically bleeding….!! Biopsies confirmed IBD! Acute Pancreatitis was the result of his IBD, not the other way around! Treatment….”Prednisone, anti-Cancer medication…etc….etc….”

    We stayed on this for a while but would have to keep him on the Prednisone….so I began looking elsewhere, for any and all options….I found a Holistic Veterinarian, (the only one in Colorado’s Front Range) who agree to take on the challenge….our goal: get him off Prednisone, while keeping his IBD under control and balance his health.

    He follows an Eastern Medicine philosophy, (Acupuncture, Hydrotherapy, Massage Therapy, Medication-Free Dental Cleanings…[which we tried and it really worked!!] We changed his diet from Z/D Ultra to “Natures Recipe, Vegetarian diet” (soy based), weaned him off Prednisone, added 3 powders to his diet to help heal and protect his gut and probiotics for digestion.

    This was a slow process and would take about 1 1/2 years….but he is FINALLY off Prednisone!! The new food gave him pretty bad gas but also developed itchy bumps on his skin, smelly ears-(yeast infection) and sometimes weepy eyes.

    Although his GI problems diminished (thankfully) the newer issues caused the Vet to suspect food allergies….so he drew blood, temporarily switched to food to “BalanceIT Catfish and Sweet Potato” diet until we got the results….($87.00 for 15lbs wasn’t going to work for a 60lb dog….or my budget..)

    Well….Drum Roll please…..2 weeks later….the golden ticket…..!

    Our precious baby is allergic to everything and I mean EVERYTHING….except, Beef, Lamb and Rice and a few veggies!!! Ever read a label on food??? Right! Got our answer but now had other challenges..

    We bought 25 lbs. of raw beef (cooked at home, fat drained off) and made white rice….result…..BAD explosive DIARRHEA in the house!!

    I forgot to add the probiotics (GNC Superfood Complex-Pet Smart)….ugh!!! Okay, added Probiotics, was better…..not totally….

    Also made “Rice Cream” (1 cup in 4 cups H20); Boil rice in water until cooked, strain off milky liquid and give with and between meals to coat GI tract and give added nourishment.

    Recently my husband found “Pure Balance Lamb and Brown Rice”…. at Pet Smart….the most basic food we’ve found…and he’s not allergic to the main ingredients!!!

    He now is a healthy 58 pounds, has a voracious appetite, is very happy and healthy with bright eyes!! He watches me cook his rice, drooling for his turn!! We’re still tweaking his diet and are extremely vigilant of any changes, especially his behaviors….

    This has been quite a journey, (emotionally, physically and financially, over $8500…thank goodness for pet insurance)…Based on what I know now, I would have tested him for food allergies FIRST….rather than last….my instincts and training (Nurse) suggested possibly GI allergies…but…I’m a people Nurse, not an animal Nurse…..and I am so thankful for all the professionals that take care of our “family members without voices” because they truly saved his life and taught us how to “speak dog language”…

    Best of luck to everyone and my hope is that experience helps others avoid or at least “think outside of the box” when faced with similar challenges…

    Wag more, Bark less….:)



  • Chrissty

    I am the person with the 9 year old English Bull Terrier with pimples between his toes. I just changed my profile picture. thanks

  • Chrissy

    If anyone has ever experienced this type of allergy and has found a solution I would be very grateful to hear about it. Thank you.