If you are able to give two weeks notice, then do so.  If you can't because of some medical emergency or whatever then talk to your supervisor.  Whatever you do, don't just not show up one day.

as stated above 2 weeks notice isn't required for any... What you want to think about is if you may want to work for the company again as quitting by just not showing up and never being seen again will probably make you ineligible to be rehired. Give as much notice as possible to stay on good terms but talk to your manager or HR if it's a health or other emergency they usually understand. Quitting on good terms is important because you may not want work for this particular company again but some companies check past employment (some don't) most former employers are too afraid of being sued to say exactly why you separated but often potential employers ask if you're eligible to be rehired. A no to that question could effect you for years.