Eye and skin irritant. Can cause sudden swelling of face, eyelids, lips, mouth and throat tissues, as well as hay fever-like symptoms. Neurotoxic. Used in some pet flea-control products.

Phenothrin is a synthetic pyrethroid that kills adult fleas and ticks. It has also been used to kill head lice in humans. Other names include Anvil, Duet, Multicide 2154, Pibutin, PT 515, S-2539, and Sumithrin.