Depending on what type of updates you have made, you may need to clear the site cache and or reindex the entire product catalog.
Clearing the cache will be necessary when you made changes to images, text, links and etc.
In the admin, navigate to SYSTEM > CACHE MANAGEMENT
Select All and Submit.
Reindexing your site will be necessary if you made changes to the product catalog such as updating prices, reorganizing products, creating new categories and etc.
In the admin, navigate to SYSTEM > INDEX MANAGEMENT
Select all indexes that are red and click Submit.
**Please note, in some instances, changes to the product catalog will take longer to be visual on the front end of your site depending on the number of products that are imported.