To test your knowledge of cosmetic labels, answer true or false to these questions, drawn from the "Consumer's Guide to Cosmetics:"

1. Cosmetic manufacturers must disclose all ingredients used.

2. Ingredients must be listed in alphabetical order.

3. Labels do not give absolute percentages of chemicals used.

4. Products labeled "for professional use only" are safe for consumer use if sold in retail stores.

5. All labels must appear on containers or packaging. Answers

1. False. Makers may add fragrance or flavorings and need not disclose their ingredients, which are considered trade secrets and are exempt from labeling requirements. The tipoff to the presence of mystery ingredients is if the phrase "and other ingredients" appears on the label. Also, chemicals having no technical or functional effect need not be listed. Products could be contaminated with "extraneous" material, which will not appear in the listing.

2. False. Ingredients must be listed in order of highest concentration by weight to the lowest.

3. True.

4. False. Products with such labels are not required by the federal government to carry ingredient lists. People with allergies should take heed. gFurther, some products can be harmful if used improperly by untrained people.

5. False. Small items such as lipsticks and mascara may have ingredient listings on an attached card or tag. Federal law requires display-rack items to have extra copies available on the counter. If they are unavailable, write to the manuafacturer, who must apply the list.