Why do some fragrances give a headache?

Probably you have also tried to experience headache in connection with smelling a fragrance. Maybe you could even recall an earlier situation, when you have got the same type of headache because of the same perfume. And you are wondering, if that contains dangerous ingredients, or something is wrong with it? There is a simple explanation to it. Scents triggers memories. Whenever we smell a particular scent, during having a special condition ( for example headache or nausea ), our brain connect theses things together, and we remember the time, when we have smelled it before. Unfortunatelly we also remember, that we felt unwell. That is also why pregnat women gets sick, when smelling coffee or fried eggs. These things are being prepared in the morning, when she felt unwell once, and her brain connected the nausea with the smell of the breakfast. Most of these scent - sickness relationships will break up after a while, but some came to stay, unfortunatelly. Myself for example, 18 years after my pregnancy, still get nausea everytime I smell fried eggs.