Imiquimod
"This cream really is a miracle.  The first few times I used it on my warts, I did not pay attention to ONLY putting it on the warts, I applied it to the general area and the itching was unbearable. But after paying closer attention to my application, my warts have very noticeably gotten smaller or disappeared after only two weeks of treatment. 
My side effects were itching, slight sting when applying, slight swelling, and just some over all discomfort. But the side effects were nothing compared to being on a wart free track!"