Click here to view this product's information sheet HeartGard® Plus Chewables for Dogs has a wide margin of safety for all sizes and breeds of dogs. It is approved for use in puppies as young as 6 weeks, small dogs regardless of weight, pregnant or breeding bitches, stud dogs, and Collies. HeartGard® Plus Chewables for Dogs is available for three weight ranges; 0-25lbs, 26-50lbs, and 51-100lbs. For dogs over 100lbs, mix and match to reach appropriate weight range. HeartGard® Plus Chewables for Dogs comes in 6-dose dispensing packs or our newer more convenient 12-dose dispensing pack. The 12-dose packaging provides the convenience of having a full year's supply of HeartGard® Plus Chewables for Dogs on hand. Dogs 6-months of age and older should be tested for heartworm disease prior to being put on a preventive program and tested annually thereafter. HEARTGARD is well tolerated. All dogs should be tested for heartworm infection before starting a preventative program. In clinical field trials, even the most common adverse reactions, vomiting and diarrhea, were observed only rarely (1.1% of doses administered). The SmartPak Heartworm Preventative Guarantee If your dog tests positive for heartworms while being administered a heartworm preventative purchased through SmartPak, we will refund the purchase price or provide replacement product and reimburse reasonable diagnostic and treatment costs for a combined total of up to $1500 to return the dog to negative heartworm status one time only per dog, provided the terms of this guarantee are met. Dogs that have previously been positive for heartworms are not eligible for this guarantee.· You must have purchased the heartworm preventative prescribed for this dog from SmartPak within 60 days of a negative heartworm test· You must have administered the heartworm preventative on a monthly basis according to the label and your veterinarian’s directions· You must have your dog tested at least every 12 months for heartworms· You must have administered the last dose of heartworm preventative within 31 days of diagnosis· You must have used the product before its expiration date as found on the package When requesting reimbursement, you must provide all of the following:· Proof of negative heartworm status within the last 12 months· Proof of current positive heartworm status· Itemized invoices and laboratory records for all diagnostic workup prior to heartworm treatment· Itemized invoices and medical records for heartworm treatment· Lot number of product used In the unlikely event your dog does not accept one of our heartworm preventatives, SmartPak will either send a new package of the product or refund the purchase price.