Comprehension of what is communicated in a text can be tested to check a text's effectiveness. In most text types, including persuasive texts, comprehension is the prerequisite for successful information processing. In this contribution the effectiveness of the South African National Department of Health's multilingual leaflet on HIV/AIDS Counselling is evaluated. The questions posed were about whether low-literate South Africans could comprehend and remember the message in the leaflet. Structured interviews were used to research these possibilities when low-literate African language speakers had read them. It was found that the majority of the respondents was not able to recall the main points of the message, or to formulate the content of key paragraphs in their own words. Despite possible inherent errors in the research design, our conclusion was that the leaflet is not effective in conveying its message among low-literate South Africans. The confusing outer structure of the leaflet and prior knowledge based on cultural understanding of the topic might have caused a cognitive overload for the readers and made the message incomprehensible to them. On the basis of our findings we designed a checklist which translates comprehensibility and memorability into textual characteristics which are measurable. This instrument can be of assistance to document designers who have to evaluate such characteristics in materials for low-literates.