# Seresto Flea and Tick Control Collar for Dogs and Puppies > For dogs and puppies Seresto is a flea and tick collar for dogs, made by Elanco. Choose by weight: 38cm for dogs up to 8kg, 70cm for dogs over 8kg. Suitable for puppies aged 7 weeks and older. Fleas: 7 to 8 months’ protection Ticks: killed and repelled for 8 months Also treats biting lice Use it... *Source: https://ashcroft4pets.co.uk/dog-flea-treatment/seresto-dog-collar/* **Seresto collar for dogs: 8 months of flea and tick control** Seresto is a slow-release collar containing two active ingredients. Imidacloprid kills adult fleas, flea larvae and biting lice (it blocks nerve signals in the parasite, causing paralysis). Flumethrin kills ticks and repels them, which helps stop them biting (it disrupts the tick’s nerve cells). Both spread from the collar across your dog’s skin and coat in low amounts while the collar is worn. **Safe use** Don’t sleep with a dog wearing the collar, especially children, and don’t let children play with it or put it in their mouths. Remove any ticks already attached when you fit the collar, and wash your hands with cold water afterwards. Some dogs get itching, redness or hair loss under the collar. Side effects are listed in the official product information below. Legal category: NFA-VPS View the official product information: [Small dogs (38cm)](https://www.vmd.defra.gov.uk/productinformationdatabase/files/QRD_Documents/QRD-Auth_1244233.PDF) | [Large dogs (70cm)](https://www.vmd.defra.gov.uk/productinformationdatabase/files/QRD_Documents/QRD-Auth_1244302.PDF)