Flat warts are caused by papillomavirus infection. This disease is highly contagious and recurrent, making treatment complex. Generally, if there are only a few at the onset, laser removal can be used, followed by topical application of interferon to prevent recurrence. If there are many flat warts, laser treatment may not be very effective. Oral and topical medications are alternative options, such as antiviral drugs and immune-boosting medications, supplemented with topical application of interferon or localized interferon injections. If these methods are not effective enough, you may consider undergoing wart immunotherapy at a hospital, which generally yields better results overall. Laser treatment is suitable for flat warts, but only when they are few in number.