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Dangers of Hartz Flea & Tick Shampoo

| Updated September 26, 2017

A product of a Secaucus, NJ based veterinary company, Hartz Flea & Tick Shampoo is a shampoo that is used on cats and dogs to treat flea and tick infestations. If left untreated, fleas and ticks can cause a host of problems to the dog or cat, such as flea allergy, tapeworm, dermatitis and flea anemia. However, some users of Hartz Flea and Tick shampoo have reported various adverse reactions to the product.


Some users have complained that this product, when used on cats and dogs, almost had the effect of killing not the fleas and ticks, but the host animal itself. According to anecdotal reports, animals treated with Hartz Flea and Tick have started showing signs of neurological issues such as epilepsy and hallucination. These were accompanied by shock, pain, swelling in the eyes and reddening of the belly. Hartz employs several potentially toxic chemicals as the active ingredients, leading to this potentially dangerous reaction. A class action lawsuit was filed regarding these reported claims, but no definitive statements have been made by a medical authority regarding the truth or falsity of these claims.

Hair Loss

Some owners have reported that pets lose some or all hair after an application of Hartz flea and tick shampoo. Many of these animals experienced itchiness before the hair loss occurred. The hair loss has not been conclusively linked to Hartz Flea and Tick Shampoo, but it occurred shortly after an application of the shampoo in several cases. In most instances, the hair eventually regrows.

Seizures and Other Neurological Problems

Some animals that were administered Hartz Flea & Tick Shampoo also experienced other cerebral dysfunctions including seizures. This occurred almost immediately after the use of the product. Other pet owners report sudden debilitation or coma after the use of Hartz Flea and Tick products. These adverse side effects are attributed to the presence in the product of organophosphate insecticides (OPs) and carbamates. Ingredients used in Hartz that pose dangers include diazinon, chlorpyrifon, naled, phosmet, dichlorvos, malathion and tetrachlorvinphos.