Dubai Municipality is investigating claims that a dog shampoo caused the death of one animal and left another seriously ill.
The authority's animal control department received reports of the death, a spokesman said, while the owner shared her Chihuahuas' plight on social media.
The vet treating the animals diagnosed blood poisoning and kidney failure.
The owner told The National she is distraught at the death but did not wish to be named or discuss it further.
In an earlier post on Facebook accompanied by pictures that were widely shared, she claimed she used Hartz Groomer Gentle Puppy Shampoo on her two dogs.
The health of both dogs rapidly deteriorated - one died within days and the second remains ill, with serious burns to its skin.
In a statement, Hartz said it was aware if the claims but insisted its products are safe and approved by authorities in the United States and the UAE, along with the other countries it sells them in.
“Hartz became aware yesterday of several social media postings that reference a private Facebook posting from a person, apparently residing in Dubai, who alleges both of her dogs were injured as a result of her using an unnamed Hartz shampoo product,” a Hartz Mountain Corporation spokesman said.
“We confirm that all Hartz flea and tick control products are registered with the US Environmental Protection Agency (EPA) in accordance with US federal law, and with all applicable state registration laws.
“These products meet all applicable EPA efficacy and state safety and efficacy testing requirements.
“We also understand the import and use of our flea and tick control shampoos is fully compliant with applicable UAE law."
The firm said it has been making animal products for almost 60 years and has a safe track record. Hartz markets seven flea and tick shampoos and six grooming shampoos in the UAE.
Similar incidents involving Hartz and other pet wash companies have been reported to the US Environmental Protection Agency (EPA) in the past but have remained unproven.
But complaints have continued against a range of adverse reactions in pets to squeeze-on flea products containing the chemicals pyrethrins, Permethrin, or other pyrethroids.
Symptoms including central nervous system damage, rashes, itching, hair-loss, appetite loss requiring veterinarian visits, medications, hospitalisations and death in extreme cases.
“As with all flea and tick topical products, whether sold through veterinarians or through retail stores, there is always a small risk of a particular animal having an adverse reaction to the application of a pesticide product,” the Hartz spokesman said.
Hartz said photographs posted on social media of the injuries sustained by the two dogs were inconsistent with those seen in previous cases where animals had suffered an adverse reaction.
“Hartz would welcome the opportunity to communicate directly with the consumer in Dubai to address her concerns," the spokesman added.
Trina Mole, who runs the online Sassy Pet Shop in the UAE, is aware of the shampoo and does not stock it because of the reported cases in America.
“There are several flea and tick products out there that seem to have a similar effect on some pets,” said Ms Mole, who is from the UK.
“Smaller dogs are more fragile in general and seem to be more vulnerable to the chemicals used.
“It is horrific when any dog is burned in this way from a chemical shampoo for fleas and ticks.
“The brands will say only a very small percentage of animals using the shampoo get sick, but that is not an excuse.
"They should be safe for all pets to use.”