Well I never new this kind of thing happend from this over the counter flea medication & it was just about a week ago I bought some & applied it to my two kittens (4 & 5 months old). They seem to be fine right now, but I’m wondering if I’m in the clear yet, or not. Does anyone know what the longest amount of time after applying the flea drops a cat can have a reaction? I’m just so worried. I just lost my 17 year old cat 3 weeks ago & I don’t think I could handle losing these two, please any info?