Recently I had a flea infestation.I purchased the various sprays, collar and the neck drop treatment, at some expense.My guide is basically warning owners of these over the counter 'prescription strength' flea treatments. The brand in question was 'Bob Martins flea treatment' collars and droppers. My experiance was that they simply do not work.AT ALL!!!.The following day my pets were still alive with fleas and actually found fleas hiding under the' toxic' collar.....I rang my vets who confirmed my suspicions. I purchased 'Frontline' from them. Next day all fleas are dead or not very happy!(dying). I'm not going to blame Mr.Martins product for legal reasons, and perhaps living in Scotland the solution doesn't work on tartan fleas............Save your money and breed the fleas for a possible circus or use a good product.