OpenAHLTA was created from AHLTA-Theater but we removed all of the costly proprietary modules in order to keep it free. The Drug-to-drug interaction checking is now optional, not required. For example, if you purchase the FDB MedKnowledge product, OpenAHLTA will automatically perform Drug-to-Drug and Drug-to-Allergy interaction checking. Below is a list of changes from AHLTA-Theater. Uses SNOMED-CT (the most comprehensive, multilingual clinical healthcare terminology in the world) The History and physical MEDCIN tree has been replaced with free text Use dragon natually speaking to dictate your own encounter note Use asutype for mistake-free, fast typing Contains free crystal reports for local reporting Immunizations module is enabled! The Dental modues exist but are disabled for the first release The Oracle database has been replace with MySQL The Medcin ICD terminology has been replaced with SNOMED-CT