Fast-acting oral flea treatment for cats weighing 2 to 25 pounds. Begin working in just 30 minutes. Achieves greater than 90% effectiveness against adult fleas on cats within 6 hours. Convenient over-the-counter oral flea treatment. No prescription needed. This oral flea tablet is intended for cats 4 weeks old old and weighing between 2 to 25 pounds. Safe for use on pregnant or breeding cats.