Johnson's 4fleas Tablets for Larger Dogs is the fastest way to kill fleas on dogs and puppies over 11kg from 4 weeks of age. Effects on the fleas may be seen as soon as 15 minutes after administration. Between 95% and 100% efficacy is observed within the first 6 hours after administration and complete efficacy is reached within 24 hours. This pack contains 6 tablets, providing a 6 treatment pack. It is for use with dogs over 11kg. The tablets start killing fleas in 15 minutes and are rapidly absorbed into your pet's bloodstream. When fleas start to feed, the tablets interfere with the fleas' nervous system, rapidly causing hyperactivity, paralysis, then death. For pets weighing between 11.1kg and 57kg, one tablet is administered when fleas are seen. For pets weighing 57kg+, two tablets are administered when fleas are seen.