Perfume

Why do some people women and men alike, feel they need to bathe in their chosen JC Penney perfume counter scent? I have a terrible sensitivity to some perfumes and have to be careful about what I wear myself. More often than not I just go without. I am now sharing office space and the chick across the hall is smelling strong, strong, strong. She is super nice and I really like her. How do I tactfully say "your stank of roses or whatever the hell it is, gives me a headache. Could you tone it down a bit?"