A migraine is a neurological condition that is frequently denoted with intense, debilitating headaches. Other symptoms of migraine may include vomiting, nausea, numbness, and tingling. Migraines are known to be triggered by factors such as caffeine, weather, foods, stress, dehydration, alcohol, lights, sounds, and smells. This heightened sensitivity, or aversion to smells, is known as osmophobia.

Research has linked various common odors, some found in everyday household items, to migraine attacks. These include:

1. Scents and perfumes
Although the use of perfumes is commonplace, products like feminine scents, deodorants, essences, aftershave, incense, candles, fresh flowers, air-fresheners, dried flowers, lavender, and vanillin, have been reported as sources of migraines. It has been theorized that because these fragrances rely more on chemical compounds than on natural oils, the scent itself is not the cause. Instead, the chemical construction and continuous exposure to the product may be the root of the migraines.

2. Smoke
Smoke from cigarettes and cigars have also been identified as causes of headaches. Smoking and inhaling secondhand smoke exposes the brain to nicotine, which changes the size of blood vessels in the brain, possibly causing a headache. Smoke also causes headaches when the smoke irritates the nose and throat or causes an allergic reaction.

3. Cleaning products
For those with a highly sensitive olfactory system, the smell of cleaning products such as soaps, shampoos, disinfectants, ammonia, bleach, and detergents are likely to trigger a headache. These migraines have been linked to the inhalation of the harmful chemical compounds in these products, which dilate blood vessels in the brain.

4. Oil derivatives
Though migraines can be commonly linked to the smell of gasoline, the odor of other oil products like kerosene, diesel oil, and kitchen gas have also been associated with these headaches. The adverse effects caused by these products is due to their chemicals, including BTEX, which is toxic. Breathing in gasoline, even in small quantities, can lead to nose and throat irritation, headaches, nausea, and vomiting.

5. Car exhaust
Much like oil derivatives, the smell from the exhaust of vehicles has been cited as an offending smell that commonly causes headaches among those who are susceptible to migraines. The fumes and vapors cause dilations of blood vessels, leading to headaches. Exhaust fumes also contain carbon monoxide, which in poorly ventilated areas, may also cause headaches.

6. Food odors
The smell of some foods like coffee, onions, fried foods, boiled and grilled meats, sweets, wine, peas, corn cobs, fish, and garlic have been associated with causing migraines. The smell of some foods like onions has been hypothesized to stimulate the trigeminal nerve, leading to inflammation. Another theory is that the smell could itself cause blood vessels to shrink, causing symptoms of migraine.

7. Beauty products
Migraineurs also have to be more selective in their choice of beauty products. Smells from commodities like cosmetics, lotions, and nail polish have also been identified as possible causes of episodes. Much like perfumes, beauty products rely on chemical compounds, which cause the blood vessels to swell and dilate, stimulating the nervous system associated with pain in the brain.

8. Harsh chemicals
Other items that trigger migraines include chemicals like pesticides, insecticides, paint, varnish, paint thinner and foul smells like sewers and sweat. The level sensitivity in migraineurs affects how the brain processes the smells. As a result, higher limbic activity is evident in people during migraines.