This lecture will focus on topical flea and tick products in both dogs and cats. Early in the lecture a focus will be made on how to differentiate paresthesia from true neurologic disease after application of permethrin and etofenprox in both dogs and cats using case examples and quizzes to encourage participation. Further case examples will be used for discussions involving the list of active ingredients in the learning objectives below. The discussion will be case based and include clinical signs, exam findings, if radiographs of flea and tick collars are helpful and treatment recommendations including a conversation of using intravenous intralipids in feline patients exposed to canine pyrethrin containing topicals.