Nauseous odors trigger the immune system.

As it turned out, unpleasant odors affect not only behavior - even after contact with them, immune cells in the mouth are activated. They are preparing to neutralize the threat. These conclusions were reached by Swedish scientists during a study involving 36 healthy people. They were given to smell 16 aromas: pleasant, neutral and disgusting. Among the latter are the smell of surströmming and rotten yeast. After evaluating the scents, the scientists collected saliva samples from the volunteers. It turned out that due to contact with disgusting odors, the tumor necrosis factor TNF-α increased. This means that the body has prepared to defend itself against potential danger. The factor also enhances sensitivity to bitter taste - this is a way to recognize a toxic threat in time.