These are vet-recommended and FDA-approved to kill adult fleas fast before they have a chance to lay eggs. This product is also FDA-approved to help prevent Lyme infections as a direct result of killing black-legged ticks. Each fast-acting chew provides safe and effective protection, killing fleas and ticks for a full month. And the chews are easy to give because dogs love the delicious beef flavor—you may even give them to your dog with or without food! Each NexGard bite-sized monthly dose is gentle enough to give to puppies and dogs as young as 8 weeks, weighing as little as 4 pounds.