(SJ-R) - That great glass of cabernet sauvignon can sometimes come with a price, a headache.

Setting aside those who suffer routinely from migraines or someone who tied one too many on the night before, even people not normally prone to headaches can sometimes feel the effect after a simple glass or two of red wine.

Sulfites often get the blame for causing the affliction, but experts said it's highly unlikely sulfites are the culprit and that two other substances are probably at fault.

Andrew Waterhouse, wine chemist in the Department of Viticulture and Enology at the University of California at Davis, said people may think sulfites are the problem because of the "contains sulfites" phrase seen on wine labels since the 1980s.

"They look at the bottle ... and they think, 'Oh my goodness, if it contains sulfites, that must be dangerous,'" he said.

Most winemakers add a small amount of sulfites to keep wine from oxidizing, and sulfites occur naturally during fermentation.

Sulfites are used to keep foods from browning, for instance, at salad bars or in dried fruit, and a very small percentage of people have a sulfite allergy, hence the Food and Drug Administration's decision to require the label, Waterhouse said.

Dr. Frederick G. Freitag, a headache specialist and associate professor at the Medical College of Wisconsin, said headache is not a common symptom of allergies.

"You never hear about 'the salad-bar headache,'" said Freitag, who has studied, for nearly 25 years, why wine might cause head pain.

Freitag said red wine headaches are likely linked to tyramine and tannins.