Phenol in household products is highly toxic to domestic cats

This is a story about the danger of using medicines for humans on domestic cats. My personal belief is that a cat caregiver should never use human medicines on their cat without first consulting their veterinarian or at the very least doing a thorough search on the Internet.

There are many household products and medicines containing substances which are toxic to domestic cats. In fact, there are many chemicals within the home which are toxic to cats such as fire retardants and carpet chemicals. They are everywhere and I don’t think enough is being done to protect the domestic cat from them.

Click this link to see many articles on the topic of ‘toxic to cats’.

Phenol kills cats
Phenol kills cats. Image: MikeB at PoC.
Two useful tags. Click either to see the articles: Toxic to cats | Dangers to cats

Felix’s story

Felix was a domestic cat living with Adrian Paul, 56, in South London, UK. Felix got into a fight with another cat and suffered scratches or bites to his face that were not that serious.

Mr Paul decided to treat his cat with a product called Germolene. It is an antiseptic cream for humans containing two active substances, phenol and chlorhexidine digluconate.

He put the product on his cat’s face. His cat was dead several days later. The moment he put Germolene on his cat’s face he killed his cat. It was a slow death due to poisoning.

I’m going to go into a lengthy description of his death because it is unpleasant but Felix quite quickly became ill and acted strangely. He was unsteady on his feet and became lethargic.

Mr Paul said: “He knocked over the water bowls – his legs all splayed out when I went to see if he was still alive, his tongue stuck out a little bit and he couldn’t reach the water.”

He called his veterinarian but Felix died before he could get him to the clinic. Adrian Paul responds to the article at the base of the page.


Phenol (carbolic acid) is one of the oldest antiseptic agents. It is highly toxic to cats because cats are deficient in the enzyme UDP-glucuronosyl transferase. Any product containing it, be it a household cleaner or disinfectant for human use, should not be in a home, shelter, veterinary clinic or any other establishment where there are domestic cats or they should be used with caution.


There will be a long list of products containing phenol, too long to list here. Update: I have a shortened list which might help. I tried to find a list but couldn’t. But such products would be the one mentioned: Germolene. Another would be TCP in the UK and Meytol and Dettol which you might be able to buy worldwide.

There will be instructions on how to use the products including the concentrations needed. People ignore instructions. If a cleaning product containing phenol is used phenol may remain on the mop or brush and become progressively more concentrated. It may remain on a hard floor if it is used at high concentration because water evaporates faster than phenol. The water evaporates leading phenol deposits on the floor. We know that domestic cats like to sit on floors.

What about a kitchen floor that has underfloor heating for example?


Phenol can be dangerous to humans as well. According to the National Institutes of Health phenol is toxic and some people can be hypersensitive to it. It can seriously harm them. Even at low exposures.

Conflicting information?

There is conflicting information on the Internet about using Germolene on cats. I have carefully researched this matter. But one website,, says quite clearly that it is safe to use Germolene on cats. The author of an article on the site states: “So, if you have a cat that has a minor cut or graze, Germolene can be safely used to treat the wound and speed up the healing process.” They never mention phenol in their article. I believe their information to be dangerously misleading as they make no reference to phenol in Germolene.


A study published in 1965 (remarkably) states that phenol destroys the nerve fibres of cats both myelinated and non-myelinated. Link:

A study published in 1987 states:

“Phenol poisoning can occur by skin absorption, vapor inhalation, or ingestion, and, regardless of route of exposure, can result in detrimental health effects. Acute toxicity has been observed in man and experimental animals, resulting in muscle weakness, convulsions, and coma. “

Link to that study:


My conclusion on researching phenol in household products is that they should be avoided if you have a cat. And they should be used with caution on oneself. I have a product called TCP which in the past I’ve used to gargle with. I have still got the product. It is carefully stored away. I may still use it but with great caution to ensure that it is not left even in small quantities in a glass or other receptacle.


Bayer is the manufacturer. They say:

“Germolene Antiseptic Cream is classified as a medicine for human use and therefore approved and regulated by the Medicines & Healthcare products Regulatory Agency (MHRA). The MHRA is the UK government agency responsible for ensuring medicines meet applicable standards of safety, quality and efficacy, including the legal requirements regarding medicines’ labelling.

Safety warnings for medicinal products are tightly regulated and we comply with strict statutory provisions that dictate what must appear on product packaging and in any package leaflet. We take great care to ensure our compliance with the relevant legislation, and can confirm that labelling of Germolene Antiseptic Cream has been approved by the MHRA.”

Dr. Scott Miller DVM, resident vet on ITV show This Morning

He said:

“Many pet parents make the mistake of using human medications and products on their animals because they are easily accessible within a shared family home. Although cats, dogs and people are all mammals, we are very different animals and react to things in very different, and sometimes, life threatening ways. Phenol is incredibly toxic to cats as it is unable to be metabolised by this species, causing poisoning leading to liver damage, neurological symptoms and even death.”

Adrian Paul’s feedback on the article

Many people may say to Adrian, “My personal belief is that a cat caregiver should never use human medicines on their cat without first consulting their veterinarian or at the very least doing a thorough search on the Internet.” (source: this article).

1. a. How do we know they are human medicines if they do not say so? In the UK and most other countries you can buy them over-the-counter in any larger grocery store without a human prescription. Other products are fine for use on animals. In the vast majority of cases, only a doctor or pharmacist would know if a product was meant “for use on humans only” (the phrase “for human use only” is ambiguous, as humans can use the product on either themselves or their pets).

b. Surely the onus should be on the pharmaceutical manufacturer to clearly label their medicinal products as to whether they are “for use on humans only”? (or the less satisfactory and somewhat misleading phrase “for human use only”) and/or “warning: this product is highly toxic to pets and other smaller animals” (or “warning: do not use on pets or other smaller animals”).

2. Vets are generally not available at weekends, plus the nature of the injuries often mean you will see no need to phone an emergency vet for advice.

3. “A thorough search on the internet” could not only take an hour or two, and your pet clearly needs urgent First Aid. It will also often lead to conflicting opinions and so-called facts (I have evidenced this recently to yourself, with just two examples of many, in relation to just Germolene).

Triclosan is harmful to cats although it is used in products for human use (2023)

Please search using the search box at the top of the site. You are bound to find what you are looking for.

2 thoughts on “Phenol in household products is highly toxic to domestic cats”

  1. If you want to hear more about my tragic story, you can e-mail me at adrian @ germolene. org . My website is Germolene .Org


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