WHAT IS fipronil spot-on? Each pipette of product contains 50mg of the active ingredient Fipronil the same as the active ingredient in Frontline. WHAT IS fipronil spot-on USED FOR? Johnson’s fipronil Spot-on is used for the treatment of infestations by fleas and ticks. Johnsons Fipronil shows immediate effect against fleas and persistent activity against new infestations for up to 5 weeks. This product kills ticks within 48 hours. Veterinary strength flea control Contains same active ingredient as the market leader For the treatment of fleas and ticks Fast acting – fleas are killed within 24 hours; ticks are killed within 48 hours Long-lasting – Effective against fleas for up to 5 weeks Use on cats and kittens from 8 weeks old Easy To Use, simply ‘Spot On’