Yes...there are rules restricting you from carrying on anything you want. Most questions I hear about carry on regulations have to do with toiletries. You can't carry on all the gels / liquids / toothpaste that you want, but you can still carry on A LOT, and thanks to the TSA, they've made it relatively easy to know the rules. All you have to remember is 3-1-1. Here's a helpful 3-1-1 carryon wallet card you can print out directly from the Transportation Security Administration.
3 - All liquids and gels must be in 3 ounce or smaller containers
1 - Those containers must be placed in a 1 quart, clear, plastic zip top bag
1 - Only 1 bag per traveler
Here's an example of what we were able to fit into a carry-on while obeying the 3-1-1 rules.
FYI: In the 1-Quart Zip-Top Bag, we fit: shampoo, conditioner, lotion, hair spray, shave cream, mouthwash, toothpaste, ibuprofen, and sudafed. Surely enough for a week long trip. If you still need more room, you may have to ask your travel mate if they have extra room. If all else fails, you'll either have to check your bag, or buy some items at your final destination.