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How To Tell If a Cat Has Worms: 8 Vet-Reviewed Signs & FAQ


May 26, 2023
a sick cat lying on the sofa


a sick cat lying on the sofa
Dr. Lorna Whittemore Photo

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One of the most unfortunate experiences for a cat owner and their cat is discovering that worms have taken up residence in your cat’s intestine. Not only is finding worms an alarming and unpleasant experience, but they can also raise health concerns for you and your cat. However, most types of worms can be treated and removed with the correct diagnoses and management.

If you have any concerns that your cat has worms you should contact your veterinary clinic for advice and effective treatments.

If the worms aren’t visible, you may be confused about whether your cat has worms or not, so we’ve compiled a list of signs that may indicate that your cat has some unwelcome guests, and we’ll answer a few frequently asked questions about these parasites.


The 8 Signs of Worms in Cats

1.  Worms Are Visible

The most obvious sign that your cat has worms is when you can visibly see them. You may notice full or half worms or eggs in their stool. Sometimes worms or eggs move to a cat’s anus and get caught in the fur. Roundworms resemble spaghetti and are commonly detected in poop or vomit.

Tapeworms are segmented, long, and flat, and your cat’s poop may contain whole tapeworms or have them protrude from the rectum. The segments can often separate and appear to look like bits of rice.

2. Weight Loss

Your cat may start to lose weight if it has worms. Even though your cat’s appetite may remain the same or even increase, it may still lose weight if they have worms present. Worms will cause weight loss because your cat will not receive as much energy from its meals, no matter how much it eats.

sick and thin cat
Image Credit: Benchamaporn Kanlapungha, Shutterstock

3. Increased Appetite

Worms may cause an increase in appetite when they are present. This is one of the common indications of worm infestation. Your cat needs to eat more food to maintain their physical condition as the worms rob them of essential nutrients. However, as we mentioned before, even with an increase in appetite, your cat may still lose weight, so the combination of weight loss and an increase in appetite may indicate that your cat has worms.

4. Vomiting & Diarrhea

Worms can cause gastrointestinal irritation, which may lead to vomiting and diarrhea. Vomiting and diarrhea are very common symptoms of worms. Cats sometimes vomit to remove hairballs, but if it’s happening more frequently than usual, worms can be to blame. Due to parasite-caused gastritis, a cat experiences chronic vomiting, which causes them to feel sick often. Certain worms can cling to the intestine’s wall, where they get their nourishment, and cause damage and inflammation, which commonly causes diarrhea.

a cat that feels sick and seems to vomit
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5. Dry & Coarse Fur

Due to malnutrition or dehydration from the worms, your cat’s fur may look dull, coarse, or clumped, along with dry skin. If a cat has worms, it will affect its overall health as the worms deplete the cat of vital nutrients, and its coat is a clear indicator that they are not well or are not receiving enough of the proper nutrients.

6. Anemia

A healthy cat should have pink gums. However, if they appear pale or white, your cat may be suffering from anemia brought on by the worms. Anemia can occur when a cat has a severe worm infestation because they latch onto the wall of the intestine causing blood loss.

Internal bleeding and bloody diarrhea are caused by some worms, such as hookworms, which attach to the intestinal wall and feed on blood.

veterinarian checks mouth of maine coon cat
Image Credit: Ermolaev Alexander, Shutterstock

7. Lethargy

As previously mentioned, worms are parasites that deprive your cat of vital nutrients and energy.  If the infestation persists long enough, your cat can suffer from malnutrition or anemia. This can lead to lethargy, and your cat can feel exhausted and weak more quickly than a healthy cat if it doesn’t get the nutrition it needs.

8. Coughing

Cats can contract heartworms, tapeworms, or lungworms, which can lead to coughing or shortness of breath. Coughing due to a worm infestation results from the worms colonizing the lungs and the surrounding area after entering the bloodstream or as they. Coughing due to worms can be seen with other signs we have discussed, such as vomiting, weight loss, and lethargy.

sick cat coughing at house porch
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How Do Felines Get Worms?

Cats can get infected with worms by touching infected feces or parasite eggs. This can happen when a cat ingests an infected host, such as rats and birds, walks through an area with eggs or infected feces, or ingests them when grooming and sharing a litter box that contains infected stools. Because some roundworms and hookworms are not species-specific, cats can pick up infected eggs from dog poop. Cats can also commonly get tapeworms from fleas.

What Type of Worms Can Cats Get?

The worms that often affect cats are tapeworms, hookworms, roundworms, and whipworms. In addition, a variety of less common cat worms can be lethal or cause significant health issues, such as heartworms, lungworms, liver flukes and stomach worms.

a sick cat lying on the couch
Image Credit: Zhuravlev Andrey, Shutterstock

How Do You Get Rid of Worms in Cats?

When worms have been diagnosed in your cat, your veterinarian will administer a dewormer to kill the worms in the intestine. Roundworm, hookworm, tapeworm, and whipworm infections can be treated with broad-spectrum prescription treatments, but they should be administered with caution and according to your veterinarian’s instructions. Your cat may need additional doses to kill the larvae that could have emerged after the initial dose.

Your vet may also advise a monthly flea prevention treatment because tapeworm infestations can reoccur if your home has fleas.

Over-the-counter treatments are also available and easily accessible. However, it is not advised to try treating your cat for worms with over-the-counter medications or natural therapies without knowing their safety and efficacy. There is no guarantee that these treatments will be effective, and some homemade concoctions could be harmful to your cat. While it may seem easier and more cost-effective, it is always best to consult your veterinary clinic for the best and safest worm treatment.

How Can You Prevent Worms in Cats?

You can help prevent worms by practicing good hygiene and using worm and flea-prevention medication. In the case of heartworm in particular prevention is very important as there are no safe treatments for cats.

Cats that hunt frequently or live with immunocompromised people should be wormed on a regular schedule, around every 3 months at a minimum.

Frequent litter box cleaning and replacement for indoor cats are critical for reducing their exposure to contaminated feces. If your cat stays outside, you should remove debris from the yard and use deterrents to keep neighborhood pets and wildlife away.

ragdoll cat being checked by the vet
Image Credit: Tatyana Vyc, Shutterstock

What Will Happen If I Don’t Treat My Cat for Worms?

Depending on the type and severity of the infestation, untreated worm infestation can cause mild to severe health issues in your cat. As larvae travel through the body’s organs and tissues to make their way to the intestine, they may cause severe skin infections, pneumonia, blindness, and convulsions.

Persistent loss of blood and essential nutrients that the intestines are supposed to absorb can lead to ongoing anemia, dehydration, and weight loss. In some cases, for example heartworm, it can be fatal.



It is common for cats to pick up worms, and preventing and treating worms comes with owning a cat. Many times there will be no obvious signs of worms and this is why your veterinarian recommends regular fecal exams. Potential signs of a worm infestation include worms or pieces of worm in stools, weight loss, increased appetite, lethargy, vomiting, diarrhea, and an overall decline in your cat’s health. If a worm infestation is left untreated, it can harm or even sadly kill your pet, so it’s essential to recognize the signs and see your vet as soon as you suspect your cat has worms.

Featured Image Credit: stokerolga, Shutterstock

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