Yes. When redeeming a Restaurant.com Gift Certificate for a dining certificate, please read the restaurant's special instructions. There are certain restrictions on the use of the dining certificates, the main one is that you have to make a minimum purchase. For example, in order to use a $10 dining certificate you need to spend at least either $15 or $20 or $25 ..., depending on the restaurant. Some restaurants do not accept dining certificates on Fridays or Saturdays, some exclude purchases of liquor in computing the minimum purchase, etc.
If you have never purchased Restaurant.com gift certificates before, you should visit the Restaurant.com website and read the FAQs and enter your zip code to see the participating restaurants in your area and each restaurant's restrictions.