<<Disclaimer: Verify this information before applying it to your situation.>> Again, thank you to those of you who helped me out on this. I appreciate the time you took!! Below is a summary of the replies I received. Douglas in Pittsburgh: Balsamic vinegar is a wine vinegar aged in wooden barrels. It is often sulfited and there is some concern that caramel color may be added. This concern is raised possibly from the tannins from the wooden barrels. Some people get bad headaches. Whether the barrels had been previously used for another product such as brandies could be a problem. Or the sulfites may bother you if you are an asthmatic. My thought is that wine vinegar is probably safer. Bob: Balsamic vinegar is made from unfermented grape juice so it is not a wine vinegar nor a grain vinegar either. There are many different grades of balsamic vinegar but all should be gluten free. I gathered this information from watching "The Frugal Gourmet" which had an entire show devoted to this. George & Gayle: Everything I've read on the list about balsamic vinegar indicates that it is not a problem. Good Greek or Italian olive oil and balsamic vinegar makes any salad a treat in our house. You should try to get the kind that has the letter API on the label. It means it is made by a family that is a member of a consortium, and is 16% traditional balsamic and at least 18 months old. Monari Federzoni with a green label, is the most common brand in gourmet shops. This is at least three years old. It has 25% traditional balsamic vinegar (which is made with must - the juice of local grapes aged in stacks of barrels like sherry. (If you have an allergy to mold spore you may want to try a little at first and wait a day or two to see if it causes a reaction). Commercial balsamic vinegar is produced in the Modena area of Italy. It contains no balsam, but got the name because it was believed to be magically medicinal, like balsam. Black label Federzoni is 8 years old and 45% traditional - as much as $20 a quarter liter bottle. Mazzetti comes in a straw wrapped bottle - smoother and sweeter. Bellilno brand is less than $3 a bottle. Colavita makes a balsamic vinegar which is very sweet-sour and somewhat cheaper. It does not have API on the label. Marvin in Florida: Balsamic vinegar: Acetic acid = 6%. Made in Modena. Balsamic vinegar is made from either Lambrusco, Trebbiano, and or Sangiovese. The vinegar is aged a minimum of 12 years. The grapes are pressed and reduced to 1/2 to 1/3 to create Saba which is used in fermentation that produces the tart=sweet taste. The wine is then stored in wood barrels: i.e.: oak, chestnut, cherry, ash, mulberry, apple, or juniper. Different woods create different undertones. The first barrels contain 60 liters each and are stored in a warm area with a vented cover for evaporation. As the barrels are evaporatng they are periodically topped with with the remaining mature vinegar. Another brand of balsamic vinegar is made from Trebbiano grapes. The juice is then heated and aged in barrels evaporating and concentrating in flavor. Well aged balsamic vinegar is deep rich brown with a sweet and sour flavor. Most balsamic vinegars found in the U.S. are not "aceto balsamico tradizionale" but unaged balsamic vinegar. These vinegars lack in body and flavor that the well aged possess, yet have a fair sweet and sour balance flavor not found in any other vinegars. Diana