There have been made efforts to develop technologies for low health literate users and evaluate them for effectiveness. We address how technology improves health literacy by identifying salient technical features to support health literacy processes and the specific needs of user populations. A systematic review of 45 published studies on technology to improve health literacy in PubMed, Direct Science, and Google Scholar up to 2014 was performed. Thirteen evaluation studies were reviewed to analyze their effectiveness. Among technological features used in technologies to improve health literacy, multimedia, interactive didactic forms with simple contents, followed by ease of use, are gaining popularity in technology to support health literacy process. Video game and virtual world are effective for young users to be engaged in learning. For seniors, technical features with ease of use like practical assistance are commonly used. This paper shows some technologies' effectiveness and discusses difficulties for the technologies failed to achieve desirable outcomes.